S1

Supporting Information

Streamlined Synthesis of Polycyclic Conjugated Hydrocarbons

Containing Cyclobutadienoids via C-H Activated Annulation and

Aromatization

Zexin Jin,† Yew Chin Teo,† Nicolo G. Zulaybar, Matthew D. Smith, Yan Xia*

Department of Chemistry, Stanford University, Stanford, California 94305, United States.

Table of Contents 1. General Information ............................................................................................................................... 2

2. Synthetic Procedures .............................................................................................................................. 3

2.1 Syntheses of starting material ............................................................................................................ 3

2.1.1. Synthesis of compound 2b ........................................................................................................... 3

2.2 Syntheses of PCHs ............................................................................................................................. 3

2.2.1 General procedure for the CANAL reaction ................................................................................ 3

2.2.2. General procedures for aromatization........................................................................................ 7

3. Supporting Figures ............................................................................................................................... 11

3.1 Unsuccessful annulation of oNBE and aryl bromide ..................................................................... 11

3.2 Determination of the stereochemistry of 3a .................................................................................... 11

3.3 UV/Vis spectra .................................................................................................................................. 12

3.4 Summary of optical and computational data .................................................................................. 13

4. X-ray Crystallographic Analysis ......................................................................................................... 14

5. TD-DFT Calculations ........................................................................................................................... 16

5.1 Computational Methods ................................................................................................................... 16

5.2 Quantum chemical calculations of the FMOs of 6’ ....................................................................... 16

6. NICS-XY-Scan Studies ......................................................................................................................... 17

6.1 Computational methods ................................................................................................................... 17

6.2 NICS-XY-Scan of biphenylene ........................................................................................................ 17

7. References .............................................................................................................................................. 18

8. NMR Spectra of New Compounds ...................................................................................................... 19

S2

1. General Information

Materials. All chemicals were obtained from commercial sources and used as received

unless otherwise noted. Dry toluene and THF were obtained from solvent purification

columns. Compounds 1e1, 2a2, 2c3, 2d4, S15 were prepared according to literature

procedures. All CANAL reactions and aromatization reactions were performed under

nitrogen in oven- or flame-dried glassware. Flash chromatography (FC) was carried out

with Silica 60 (230-400 mesh; Fisher). Analytical thin-layer chromatography (TLC) was

carried out using 0.2 mm silica gel plate (silica gel 60, F254, EMD chemical).

Characterizations. 1H and 13C NMR spectra were recorded in CDCl3 using 300 MHz, 400

MHz, or 500 MHz Varian NMR spectrometers. Chemical shifts are reported in ppm using

the residual protiated solvent as an internal standard (CDCl3 1H: 7.26 ppm and 13C: 77.0

ppm; d4-1,2-dichlorobenzene 1H: 6.94 ppm and 13C: 127.0 ppm). Data are reported as

follows: chemical shift, multiplicity (s = singlet, d = doublet, dd = doublet of doublets, t =

triplet, q = quartet, m = multiplet, br = broad signal, and associated combinatoins), coupling

constant(s) (Hz), and integration. ESI or APCI MS was obtained using Waters Acquity

QDa or SQ mass spectrometers. UV–Vis spectra were recorded on a Thermo Scientific

Genesys 10S spectrophotometer with background correction using pure solvent.

S3

2. Synthetic Procedures

2.1. Syntheses of starting material

2.1.1. Synthesis of compound 2b

5,8-dimethyl-5,8-dihydro-5,8-epoxynaphtho[2,3-d][1,3]dioxole (2b): A 100 mL round-

bottom flask was flame-dried and cooled under a stream of nitrogen. The flask was charged

with 5,6-dibromo-1,3-benzodioxole (S1, 2 g, 7.2 mmol) and 2,5-dimethylfuran (2.6 ml, 36

mmol) dissolved in dry toluene (30 ml). The solution was cooled at -78 °C and 1.6M nBuLi

in hexane (4.9 ml, 7.84 mmol) was slowly added to the solution using a syringe pump over

1 hour. After the addition was complete, the solution was warmed to room temperature and

the reaction was stirred overnight. The reaction was quenched with water (50 ml), extracted

with EtOAc (3 x 40 ml), and dried over Na2SO4. The solution was concentrated in vacuo

and the residue was purified by column chromatography (1:4 EA/hexanes) to yield 2c as

white solid (1.3 g, 84% yield). 1H NMR (400 MHz, Chloroform-d) δ 6.79 (s, 2H), 6.71 (s,

2H), 5.90 (dd, J = 12.8, 1.4 Hz, 2H), 1.85 (s, 6H); 13C NMR (100 MHz, Chloroform-d) δ

147.43, 147.41, 144.44, 102.56, 101.41, 88.97, 15.62. MS: m/z calculated for C13H12O3

[M+H+]: 217.08; found: 217.09.

2.2. Syntheses of PCHs

2.2.1 General procedure for the CANAL reaction

To an oven-dried 15 mL pressure tube was added palladium acetate (2.8 mg, 0.0125 mmol)

and ligand (0.025 mmol). The tube was then transferred to a glovebox, and cesium

carbonate (81.3 mg, 0.25 mmol), aryl bromide (0.25 mmol), benzo-oxanorbornadiene (0.25

mmol), and 1 mL solvent were added. The tube was closed and taken outside glovebox.

The mixture was stirred at room temperature for 5 minutes, and then heated to 130 °C.

After 24 hours, the reaction was cooled to room temperature, and was passed through a

thin layer of Celite to remove the inorganic salt. CHCl3 (2×5 mL) was then used to wash

the residue on Celite. The combined organic solution was concentrated to dryness and the

crude product was used to determine conversion by 1H NMR spectroscopy with mesitylene

added as the internal standard.

exo-5,10-dimethyl-4b,5,10,10a-tetrahydro-5,10-epoxybenzo[b]biphenylene (3a): The

product was purified by flash chromatography (1:20 EA/hexanes) as a white solid (56.4

mg, 91% yield). 1H NMR (400 MHz, Chloroform-d): δ 7.30 (dd, J = 5.3, 3.0 Hz, 2H), 7.27

S4

– 7.23 (m, 4H), 7.21 – 7.17 (m, 2H), 3.44 (s, 2H), 1.80 (s, 6H); 13C NMR (100 MHz,

Chloroform-d): δ 148.46, 143.59, 128.23, 126.93, 122.97, 118.60, 83.78, 55.83, 14.48. MS:

m/z calculated for C18H16O [M+H+]: 249.12; found: 249.11.

exo-2-(tert-butyl)-5,10-dimethyl-4b,5,10,10a-tetrahydro-5,10-epoxybenzo[b]biphen-

ylene (3b): The product was purified by flash chromatography (1:20 EA/hexanes) as a

white solid (68.4 mg, 90% yield). 1H NMR (400 MHz, Chloroform-d) δ: 7.36 (dd, J = 7.7,

1.6 Hz, 1H), 7.26 (m, 4H), 7.24 (s, 1H), 7.14 (dd, J = 7.7, 0.9 Hz, 1H), 3.42 (d, J = 1.2 Hz,

2H), 1.82 (d, J = 2.2 Hz, 6H), 1.35 (s, 9H); 13C NMR (100 MHz, Chloroform-d) δ 151.38,

148.58, 148.56, 143.08, 140.37, 126.90, 125.35, 122.42, 120.00, 118.59, 83.82, 83.76,

55.60, 55.38, 35.36, 31.97, 14.56, 14.54. MS: m/z calculated for C22H24O [M+H+]: 305.18;

found: 305.13

exo-2-methoxy-5,10-dimethyl-4b,5,10,10a-tetrahydro-5,10-epoxybenzo[b]bipheny-

lene (3c): The product was purified by flash chromatography (1:10 EA/hexanes) as a white

solid (57.3 mg, 87% yield). 1H NMR (400 MHz, Chloroform-d): δ 7.25 – 7.21 (m, 4H),

7.11 (d, J = 8.0 Hz, 1H), 6.87 – 6.83 (m, 1H), 6.80 (d, J = 2.2 Hz, 1H), 3.81 (s, 3H), 3.37

(d, J = 1.0 Hz, 2H), 1.79 (d, J = 9.4 Hz, 6H); 13C NMR (100 MHz, Chloroform-d): δ 160.38,

148.49, 148.41, 144.39, 135.18, 126.95, 126.91, 123.92, 118.61, 114.51, 109.24, 83.87,

83.65, 55.73, 54.98, 54.93, 14.54, 14.42. MS: m/z calculated for C19H18O2 [M+H+]: 279.13;

found: 279.06

exo-5,10-dimethyl-2-(methylthio)-4b,5,10,10a-tetrahydro-5,10-epoxybenzo[b]biph-

enylene (3d): The product was purified by flash chromatography (1:10 EA/hexanes) as a

light yellow solid (54.1 mg, 81% yield). 1H NMR (300 MHz, Chloroform-d): δ 7.27 – 7.24

(m, 4H), 7.23 (dd, J = 1.5, 0.5 Hz, 1H), 7.15 (d, J = 1.4 Hz, 1H), 7.14 – 7.09 (m, 1H), 3.41

(d, J = 1.8 Hz, 2H), 2.49 (s, 3H), 1.79 (d, J = 4.1 Hz, 6H). 13C NMR (75 MHz, Chloroform-

d): δ 148.36, 148.33, 144.17, 140.77, 138.26, 127.65, 127.04, 127.02, 123.38, 122.23,

118.65, 83.89, 83.77, 55.62, 55.51, 17.20, 14.54, 14.47. MS: m/z calculated for C19H18OS

[M+H+]: 295.11; found: 295.07

S5

exo-2-(tert-butyl)-7,12-dimethyl-6b,7,12,12a-tetrahydro-7,12-epoxynaphtho-

[2',3':3,4]cyclobuta[1,2-a]pyrene (3e): The product was purified by flash

chromatography (1:25 EA/hexanes) as a white solid (81.0 mg, 76% yield). 1H NMR (400

MHz, Chloroform-d): δ 8.24 – 8.18 (m, 2H), 8.14 – 8.00 (m, 4H), 7.96 (s, 1H), 7.40 – 7.27

(m, 4H), 3.97 (d, J = 3.6 Hz, 1H), 3.77 (d, J = 3.6 Hz, 1H), 1.97 (d, J = 10.3 Hz, 6H), 1.58

(s, 9H); 13C NMR (100 MHz, Chloroform-d): δ 148.66, 148.64, 148.46, 140.90, 137.91,

132.27, 131.03, 131.01, 128.95, 128.27, 127.09, 127.08, 127.00, 126.24, 125.47, 123.96,

122.71, 122.62, 122.44, 119.07, 118.77, 118.75, 84.77, 84.11, 55.77, 55.74, 35.43, 32.20,

15.76, 14.60. MS: m/z calculated for C32H28O [M+H+]: 429.21; found: 429.15

exo-5,10-dimethyl-4b,5,10,10a-tetrahydro-5,10-epoxybenzo[b]biphenylene-2-

carbonitrile (3f): The product was purified by flash chromatography (1:20 EA/hexanes)

as a white solid (40.1 mg, 59% yield). 1H NMR (400 MHz, Chloroform-d): δ 7.62 (dd, J =

7.6, 1.2 Hz, 1H), 7.46 (s, 1H), 7.32 – 7.28 (m, 1H), 7.27 – 7.26 (m, 4H), 3.51 (q, J = 3.8

Hz, 2H), 1.80 (d, J = 1.4 Hz, 6H); 13C NMR (100 MHz, Chloroform-d): δ 149.40, 147.75,

147.71, 144.75, 132.88, 127.34, 127.32, 126.26, 123.82, 119.69, 118.78, 118.72, 111.91,

83.88, 83.82, 77.46, 56.48, 55.91, 14.42, 14.37. MS: m/z calculated for C19H15NO [M+H+]:

274.12; found: 274.08

exo-5,10-dimethyl-2-nitro-4b,5,10,10a-tetrahydro-5,10-epoxybenzo[b]biphenylene

(3g): The product was purified by flash chromatography (1:20 EA/hexanes) as a light

yellow solid (37.0 mg, 51% yield). 1H NMR (400 MHz, Chloroform-d): δ 8.30 – 8.24 (m,

1H), 8.08 – 8.03 (m, 1H), 7.37 – 7.32 (m, 1H), 7.30 – 7.26 (m, 4H), 3.53 (d, J = 1.0 Hz,

2H), 1.83 (d, J = 7.8 Hz, 6H); 13C NMR (100 MHz, Chloroform-d): δ 151.57, 148.72,

147.75, 147.65, 144.89, 127.41, 127.36, 124.64, 123.67, 118.84, 118.73, 118.43, 83.92,

83.88, 56.10, 55.46, 14.44, 14.36. MS: m/z calculated for C18H15NO3 [M+H+]: 294.11;

found: 294.04

S6

exo-5,10-dimethyl-5,5a,9b,10-tetrahydro-5,10-epoxybenzo[3',4']cyclobuta[1',2':6,7]-

naphtho[2,3-d][1,3]dioxole (3h): The product was purified by flash chromatography (1:20

EA/hexanes) as a white solid (65.2 mg, 89% yield). 1H NMR (400 MHz, Chloroform-d): δ

7.29 (dd, J = 5.3, 3.0 Hz, 2H), 7.17 (dd, J = 5.3, 3.0 Hz, 2H), 6.76 (s, 2H), 6.03 – 5.90 (m,

2H), 3.41 (s, 2H), 1.75 (s, 6H); 13C NMR (100 MHz, Chloroform-d): δ 146.46, 143.79,

142.33, 128.19, 122.92, 101.49, 101.17, 83.82, 56.06, 14.58. MS: m/z calculated for

C19H16O3 [M+H+]: 293.11; found: 293.02

exo-5,10-dimethyl-4b,5,10,10a-tetrahydro-5,10-epoxybenzo[b]biphenylene-7-

carbonitrile (3i): The product was purified by flash chromatography (1:20 EA/hexanes)

as a white solid (62.2 mg, 95% yield). 1H NMR (400 MHz, Chloroform-d) δ 7.59 (dd, J =

7.5, 1.3 Hz, 1H), 7.51 (dd, J = 1.4, 0.7 Hz, 1H), 7.37 – 7.32 (m, 3H), 7.21 (dq, J = 3.9, 1.4,

0.9 Hz, 2H), 3.44 (d, J = 1.5 Hz, 2H), 1.81 (s, 6H). 13C NMR (100 MHz, Chloroform-d) δ

153.48, 149.66, 142.67, 142.49, 132.18, 128.65, 128.64, 123.11, 122.14, 119.54, 119.37,

110.73, 84.03, 83.82, 55.14, 54.92, 14.31, 14.27. MS: m/z calculated for C19H15NO

[M+H+]: 274.12; found: 274.08

exo-5,10-dimethyl-7-nitro-5,5a,9b,10-tetrahydro-5,10-epoxybenzo[3',4']cyclobuta-

[1',2':6,7]naphtho[2,3-d][1,3]dioxole (3j): The product was purified by flash

chromatography (1:20 EA/hexanes) as a white solid (35.4 mg, 42% yield). 1H NMR (400

MHz, Chloroform-d) δ 8.33 – 8.20 (m, 1H), 8.14 – 7.94 (m, 1H), 7.31 (dd, J = 8.0, 0.8 Hz,

1H), 6.78 (dd, J = 4.6, 0.6 Hz, 2H), 6.04 – 5.93 (m, 2H), 3.49 (d, J = 1.1 Hz, 2H), 1.77 (d,

J = 8.0 Hz, 6H); 13C NMR (100 MHz, Chloroform-d) δ 151.53, 148.42, 146.63, 146.60,

144.87, 141.41, 141.32, 124.35, 123.32, 118.09, 101.42, 101.03, 100.93, 83.71, 83.67,

56.09, 55.44, 14.28, 14.18. MS: m/z calculated for C19H15NO5 [M+H+]: 274.12; found:

274.08

S7

((5,9,14,18-tetramethyl-5,5a,8b,9,14,14a,17b,18-octahydro-5,18:9,14-diepoxynaphth-

o[2',3':3,4]cyclobuta[1,2-b]naphtho[2',3':3,4]cyclobuta[1,2-i]anthracene-7,16-diyl)-

bis(ethyne-2,1-diyl))bis(triisopropylsilane) (S2) : 2 equiv. 2a and 1 equiv. 1j were used

for the reaction. The product was purified by flash chromatography (1:20 EA/hexanes) as

an orange solid (97.2 mg, 88% yield). 1H NMR (400 MHz, Chloroform-d) δ 8.43 (s, 4H),

7.34 – 7.26 (m, 8H), 3.72 (s, 4H), 1.91 (s, 12H), 1.29 (dd, J = 6.3, 1.7 Hz, 42H); 13C NMR

(100 MHz, Chloroform-d) δ 148.46, 142.43, 133.36, 127.12, 120.15, 119.44, 118.73,

104.83, 103.40, 94.66, 85.04, 56.37, 19.13, 19.12, 14.17, 11.79. MS: m/z calculated for

C60H70O2Si2 [M+H+]: 878.49; found: 879.7

2.2.2. General procedures for aromatization

Three methods have been used to aromatize the CANAL products, depending on the

substrates. Method 1 was used for all the AB type of substrates, and Method 2 was used

for ABA type of substrates.

Method 1 (PPTS/Toluene): The CANAL product and 10 equiv. pyridinium p-

toluenesulfonate (PPTS) were dissolved in toluene. The solution was heated at 120 °C for

12 hours. The reaction mixture was cooled and washed with water, and extracted with

DCM. The combined organic layer was concentrated. The solid was washed with MeOH,

collected by filtration, and washed with cold MeOH to obtain pure aromatized product.

Method 2 (HCl/iPrOH): The CANAL product was dissolved in 1 mL isopropanol/0.2 mL

chloroform and 0.2 ml HCl (37%). The solution was heated at 80°C for 24 hours. The

reaction mixture was cooled and aromatized product had crushed out of the solution. The

solid was washed with MeOH and collected by filtration to obtain pure aromatized product.

5,10-dimethylbenzo[b]biphenylene (4a): Compound 3a (42 mg) was converted to 4a as

a white solid (36 mg, 93% yield) using Method 1. 1H NMR (400 MHz, Chloroform-d): δ

7.63 (dd, J = 6.1, 3.4 Hz, 2H), 7.32 (dd, J = 6.1, 3.3 Hz, 2H), 6.93 (d, J = 1.0 Hz, 4H), 2.37

(s, 6H); 13C NMR (100 MHz, Chloroform-d): δ 150.08, 144.32, 135.91, 128.84, 125.92,

124.78, 121.17, 119.08, 14.78. MS: m/z calculated for C18H14 [M+]: 230.11; found: 230.05

S8

2-(tert-butyl)-5,10-dimethylbenzo[b]biphenylene (4b): Compound 3b (34 mg) was

converted to 4b as a beige solid (28 mg, 88% yield) using Method 1. 1H NMR (400 MHz,

Chloroform-d) δ 7.74 – 7.56 (m, 2H), 7.36 – 7.29 (m, 2H), 7.03 (t, J = 1.2 Hz, 1H), 6.96

(dd, J = 7.5, 1.5 Hz, 1H), 6.87 (dd, J = 7.5, 0.9 Hz, 1H), 2.37 (d, J = 14.3 Hz, 6H), 1.31 (s,

9H); 13C NMR (100 MHz, Chloroform-d) δ 152.38, 149.88, 147.14, 144.31, 144.21,

135.98, 135.86, 125.78, 125.68, 125.09, 124.70, 124.66, 120.77, 120.41, 118.62, 117.02,

35.46, 31.48, 29.96, 14.90, 14.74. MS: m/z calculated for C22H22 [M+H+]: 287.17; found:

287.03

2-methoxy-5,10-dimethylbenzo[b]biphenylene (4c): Compound 3c (30 mg) was

converted to 4c as white solid (24 mg, 86% yield) using Method 1. 1H NMR (400 MHz,

Chloroform-d) δ 7.68 – 7.47 (m, 2H), 7.38 – 7.26 (m, 2H), 6.85 (d, J = 7.7 Hz, 1H), 6.62

(d, J = 2.1 Hz, 1H), 6.40 (dd, J = 7.8, 2.1 Hz, 1H), 3.79 (s, 3H), 2.34 (d, J = 10.9 Hz, 6H); 13C NMR (101 MHz, Chloroform-d) δ 160.80, 151.30, 143.90, 142.92, 142.05, 136.25,

135.61, 126.00, 125.51, 124.76, 124.52, 121.26, 119.87, 119.22, 111.56, 108.30, 55.73,

29.96, 14.76, 14.61. MS: m/z calculated for C19H16O [M+H+]: 261.12; found: 261.03

(5,10-dimethylbenzo[b]biphenylen-2-yl)(methyl)sulfane (4d): Compound 3d (44 mg)

was converted to 4d as a beige solid (38 mg, 90% yield) using Method 1. 1H NMR (400

MHz, Chloroform-d): δ 7.67 – 7.57 (m, 2H), 7.36 – 7.28 (m, 2H), 6.92 – 6.87 (m, 1H), 6.82

(qd, J = 7.4, 1.2 Hz, 2H), 2.48 (s, 3H), 2.34 (d, J = 6.9 Hz, 6H); 13C NMR (100 MHz,

Chloroform-d): δ 150.33, 146.91, 143.76, 143.55, 139.02, 136.04, 135.66, 126.40, 126.10,

125.89, 124.84, 124.73, 121.62, 120.92, 119.22, 118.08, 16.55, 14.84, 14.79. MS: m/z

calculated for C19H16S [M+H+]: 277.10; found: 277.00

S9

2-(tert-butyl)-7,12-dimethylnaphtho[2',3':3,4]cyclobuta[1,2-a]pyrene (4e): Compound

3e (37 mg) was converted to 4e as a yellow solid (28 mg, 80% yield) using Method 1. 1H

NMR (400 MHz, Chloroform-d): δ 8.04 (dd, J = 21.5, 1.8 Hz, 2H), 7.96 – 7.80 (m, 4H),

7.70 – 7.65 (m, 1H), 7.63 – 7.59 (m, 1H), 7.58 (s, 1H), 7.33 – 7.28 (m, 2H), 2.67 (s, 3H),

2.44 (s, 3H), 1.56 (s, 9H). 13C NMR (100 MHz, Chloroform-d): δ 149.08, 147.03, 145.56,

144.57, 144.46, 136.48, 136.25, 132.88, 131.61, 131.41, 129.25, 128.15, 127.34, 126.64,

126.06, 125.04, 124.76, 124.51, 124.08, 123.11, 122.94, 121.28, 121.12, 115.44, 35.33,

32.04, 16.34, 14.81. MS: m/z calculated for C32H26 [M+]: 410.20; found: 410.3

5,10-dimethylbenzo[b]biphenylene-2-carbonitrile (4f): Compound 3f (30 mg) was

converted to 4f as a yellow solid (27 mg, 96% yield) using Method 1. 1H NMR (400 MHz,

Chloroform-d): δ 7.78 – 7.59 (m, 2H), 7.45 – 7.31 (m, 2H), 7.28 – 7.25 (m, 1H), 7.07 (t, J

= 1.1 Hz, 1H), 6.96 (dd, J = 7.3, 1.0 Hz, 1H), 2.39 (d, J = 6.0 Hz, 6H); 13C NMR (100

MHz, Chloroform-d): δ 154.49, 150.50, 142.41, 142.19, 136.07, 135.79, 134.63, 126.94,

126.73, 125.33, 125.25, 124.30, 123.47, 120.47, 119.59, 118.86, 111.51, 94.67, 14.94,

14.91. MS: m/z calculated for C19H13N [M+]: 255.10; found: 255.02

5,10-dimethyl-2-nitrobenzo[b]biphenylene (4g): Compound 3g (33 mg) was converted

to 4g as a yellow solid (30 mg, 96% yield) using Method 1. 1H NMR (400 MHz,

Chloroform-d): δ 7.89 (dd, J = 7.8, 1.8 Hz, 1H), 7.68 (dt, J = 7.1, 2.2 Hz, 2H), 7.64 (d, J =

1.7 Hz, 1H), 7.45 – 7.33 (m, 2H), 6.95 (d, J = 7.8 Hz, 1H), 2.40 (d, J = 2.2 Hz, 6H); 13C

NMR (100 MHz, Chloroform-d): δ 156.58, 150.85, 148.35, 141.55, 141.04, 136.33,

135.78, 127.11, 126.82, 126.25, 125.45, 125.30, 124.75, 123.75, 118.23, 113.47, 14.92,

14.86. MS: m/z calculated for C18H13NO2 [M+H+]: 276.09; found: 276.00

5,10-dimethylbenzo[3',4']cyclobuta[1',2':6,7]naphtho[2,3-d][1,3]dioxole (4h):

Compound 3h (37.5 mg) was converted to 4h as a white solid (29 mg, 82% yield) using

Method 1. 1H NMR (400 MHz, Chloroform-d): δ 7.04 (s, 2H), 6.86 (q, J = 1.4 Hz, 4H),

6.00 (s, 2H), 2.29 (s, 6H); 13C NMR (100 MHz, Chloroform-d) δ 150.24, 147.06, 143.56,

132.01, 128.43, 121.12, 118.42, 103.36, 101.36, 15.20. MS: m/z calculated for C19H14O2

[M+]: 274.10; found: 274.03

S10

5,10-dimethylbenzo[b]biphenylene-7-carbonitrile (4i): Compound 3i (26 mg) was

converted to 4i as a beige solid (22 mg, 92% yield) using Method 1. 1H NMR (400 MHz,

Chloroform-d): δ 7.98 – 7.79 (m, 1H), 7.72 – 7.62 (m, 1H), 7.49 (dd, J = 8.4, 1.7 Hz, 1H),

6.99 (q, J = 1.4 Hz, 4H), 2.35 (s, 6H); 13C NMR (100 MHz, Chloroform-d): δ 149.61,

149.34, 147.71, 146.04, 138.86, 135.91, 129.89, 129.66, 129.38, 127.80, 125.47, 120.72,

120.58, 119.90, 119.76, 108.98, 14.65, 14.58. MS: m/z calculated for C19H13N [M+]:

255.10; found: 255.00

5,10-dimethyl-7-nitrobenzo[3',4']cyclobuta[1',2':6,7]naphtho[2,3-d][1,3]dioxole(4j): Compound 3j (36 mg) was converted to 4j as a red solid (27 mg, 80% yield) using Method

1. 1H NMR (400 MHz, o-dichlorobenzene-d4) δ 7.60 (d, J = 7.7 Hz, 1H), 7.31 (s, 1H), 6.81

(s, 2H), 6.52 (d, J = 7.5 Hz, 1H), 5.74 (s, 2H), 2.07 (d, J = 2.9 Hz, 6H); 13C NMR cannot

be obtained due to the poor solubility. MS: m/z calculated for C19H13NO4 [M+]: 319.08;

found: 319.22

((5,9,14,18-tetramethylnaphtho[2',3':3,4]cyclobuta[1,2-b]naphtho[2',3':3,4]cyclo-

buta[1,2-i]anthracene-7,16-diyl)bis(ethyne-2,1-diyl))bis(triisopropylsilane) (6):

Compound S2 (30 mg) was converted to 6 as an orange solid (23 mg, 80% yield) using

Method 2. 1H NMR (500 MHz, o-dichlorobenzene-d4) δ 8.17 (s, 4H), 7.74 (dd, J = 6.3, 3.4

Hz, 4H), 7.34 (dd, J = 6.3, 3.3 Hz, 4H), 2.56 (s, 12H), 1.40 (d, J = 2.7 Hz, 42H); 13C NMR

(125 MHz, o-dichlorobenzene-d4) δ 147.51, 143.85, 136.35, 135.33, 126.24, 125.06,

124.23, 115.33, 104.81, 103.68, 19.10, 14.23, 12.21. MS: m/z calculated for C60H66Si2

[M+]: 842.47; found: 842.05

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3. Supporting Figures

3.1 Unsuccessful annulation of oNBE and aryl bromide

Figure S1. Unsuccessful CANAL reaction. Conditions: 5 mol% Pd(OAc)2, 10 mol% PPh3,

1 equiv. Cs2CO3, [substrate] = 0.25 M at 130 °C.

3.2 Determination of the stereochemistry of 3a

Figure S2. a) Heteronuclear single quantum coherence-NMR (HSQC-NMR) of 3a. b)

Heteronuclear Multiple Bond Correlation-NMR (HMBC-NMR) of 3a.

The torsion angle of Ha-C-C-C2 was calculated to be 168° and 55° in the energy-minimized

structures of the endo and exo products, respectively. High 3J-coupling constant is expected

for torsion angles of 0° and 180° and no or small 3J-coupling constant is expected for

torsion angles around 90°. In HMBC-NMR, the absence J3-coupling between Ha and C2

suggested the exo structure.6

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3.3 UV/Vis spectra

Figure S3. Normalized absorption spectra of Compound 4a-4j in chloroform.

Figure S4. Normalized absorption spectra of Compound 6 with CANAL precursor S2 in

chloroform.

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3.4 Summary of optical and computational data

Table S1. Optical and Computational Data for CBD-Containing PCHs.

Compound λonset

a

(nm)

Eg, opt

(eV)

Eg, calb

(eV) HOMOcal

c (eV) LUMOcald (eV)

4a 398 3.12 3.50 -5.71 -2.21

4b 399 3.11 3.48 -5.61 -2.13

4c 412 3.01 3.35 -5.46 -2.11

4d 414 2.99 3.28 -5.44 -2.16

4e 466 2.66 2.85 -5.30 -2.45

4f 417 2.97 3.27 -6.18 -2.91

4g 468 2.65 2.87 -6.30 -3.43

4h 406 3.05 3.30 -5.41 -2.11

4i 413 3.00 3.33 -6.13 -2.80

4j 509 2.44 2.64 -5.93 -3.29

6 500 2.48 2.54 -5.40 -2.86 aMeasured in CHCl3 solution. bCalculated by TD-DFT. cCalculated by DFT. dCalculated from

HOMOcal+Eg, cal

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4. X-ray crystallographic analysis

A crystal was coated with Paratone-N oil, attached to a Mitegen® loop or

micromesh mount, and transferred to a Bruker D85 diffractometer equipped with a Photon

100 CMOS detector at Beamline 11.3.1 at the Advanced Light Source at the Lawrence

Berkeley National Lab. Synchrotron X-rays of wavelength λ = 0.7749 Å were

monochormated using silicon (111). Frames were collected using and ϕ and scans and

the unit-cell parameters were refined against all data. Data were integrated and corrected

for Lorentz and polarization effects using SAINT v8.34A and were corrected for absorption

effects using SADABS V2014/2.7 The structure was solved using the intrinsic phasing

method implemented in APEX2. It was refined against all data using SHELXTL8,9 and

OLEX210 software.11 Hydrogen atoms were inserted at idealized positions and refined

using a riding model with an isotropic thermal parameter 1.2 or 1.5 times that of the

attached non-methyl carbon or methyl carbon, respectively. Thermal parameters for all

non-hydrogen atoms were refined anisotropically.

The X-ray crystallographic coordinates for structures reported in this article have

been deposited at the Cambridge Crystallographic Data Centre (CCDC), under deposition

number CCDC 1508923. These data can be obtained free of charge from CCDC via

http://www.ccdc.cam.ac.uk/data_request/cif.

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Table S2. Crystallographic dataa for 6

6

Empirical Formula C60H66Si2

Formula Weight, g∙mol1 843.30

Temperature, K 100(2)

Crystal System Monoclinic

Space group P21/n

a, Å 8.3902(4)

b, Å 21.3216(11)

c, Å 13.1829(6)

Volume, Å3 2357.0(2)

Z 2

Density (calculated), g∙cm3 1.188

Absorption coefficient, mm1 0.140

F(000) 908

Crystal size, mm3 0.1 × 0.03 × 0.03

θ range, ° 2.679 to 29.819

Index ranges

–10 h 10

–26 k 26

–16 l 16

Reflections collected/unique 31685/4824

Completeness to θmax 1.000

Max. and min. transmission 0.5641, 0.4994

Data/restraints/parameters 4824/0/288

Goodness-of-fit on F2 1.018

Final R indices [I > 2(I)]b R1 = 0.0473

wR2 = 0.1143

R indices (all data)b R1 = 0.0677

wR2 = 0.1240

Largest diff. peak and hole,

e∙Å3 0.433, –0.414

aObtained with monochromated synchrotron (λ = 0.7749 Å) radiation bR1 = ||Fo| – |Fc||/|Fo|, wR2 = [w(Fo

2 – Fc2)2/(Fo

2)2]1/2

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5. TD-DFT Calculations

5.1 Computational Methods

All calculations were performed using the Gaussian 0912 program package. 6’ is a

simplified model of 6 with TIPS substituents replaced with TMS. The geometries of these

molecules were first optimized at the B3LYP level of density functional theory (DFT) with

the 6-311+G(d) basis set, and the energy were then calculated with the 6-311++G(d) basis

set. All structures are ground-state minima according to the analysis of their harmonic

vibrational analytical frequencies computed at the same level, which show no imaginary

frequencies. The first six vertical transition energies were calculated by time-dependent

density functional theory (TD-DFT) at the B3LYP/6-311++G(d) level of theory.

5.2 Quantum Chemical Calculations of the FMOs of 6’

6’:HOMO 6’:LUMO

Figure S5. Quantum-chemical calculations (B3LYP 6-311+G(d)//B3LYP 6-311++G(d))

of the FMOs for compound 6’.

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6. NICS-XY-Scan Studies

6.1 Computational methods

Gaussian 0912 was used for all the calculations. All the molecules under study underwent

full geometry optimization at the B3LYP/6-311+G(d) computational level. 6’ is a

simplified model of 6 with TIPS substituents replaced with TMS. Nucleus independent

chemical shifts (NICS) calculations of 6’ and biphenylene are at the GIAO-B3LYP/6-

311+G(d) computational level and were all carried out using the Aroma package13

according to published procedures.14 The NICS-XY-scans shown contain the NICSπ,ZZ

values from the sigma only model.

6.2 NICS-XY-Scan of biphenylene

Figure S6. NICS-XY scans (NICSπ,ZZ (σ-only)) of biphenylene.

S18

7. References

(1) Figueira-Duarte, T. M.; Simon, S. C.; Wagner, M.; Druzhinin, S. I.; Zachariasse,

K. A.; Müllen, K. Angew. Chem. Int. Ed. 2008, 47, 10175.

(2) Zhou, H.; Li, J.; Yang, H.; Xia, C.; Jiang, G. Org. Lett. 2015, 17, 4628.

(3) Ikawa, T.; Yamamoto, R.; Takagi, A.; Ito, T.; Shimizu, K.; Goto, M.; Hamashima,

Y.; Akai, S. Adv. Synth. Catal. 2015, 357, 2287.

(4) Ashton, P. R.; Brown, G. R.; Isaacs, N. S.; Giuffrida, D.; Kohnke, F. H.; Mathias,

J. P.; Slawin, A. M. Z.; Smith, D. R.; Stoddart, J. F.; Williams, D. J. J. Am. Chem.

Soc. 1992, 114, 6330.

(5) Blanchot, M.; Candito, D. A.; Larnaud, F.; Lautens, M. Org. Lett. 2011, 13, 1486.

(6) Parkhurst, R. R.; Swager, T. M. J. Am. Chem. Soc. 2012, 134, 15351.

(7) Bruker AXS Inc.: Madison, Wisconsin, 2007.

(8) Sheldrick, G. M. Acta Crystallogr., Sect. A: Found. Crystallogr. 2008, 64, 112.

(9) Sheldrick, G. M. Göttingen, 1997.

(10) Dolomanov, O. V.; Bourhis, L. J.; Gildea, R. J.; Howard, J. A. K.; Puschmann, H.

J. Appl. Crystallogr. 2009, 42, 339.

(11) Müller, P.; Herbst-Irmer, R.; Spek, A. L.; Schneider, T. R.; Sawaya, M. R. Crystal

Structure Refinement: A Crystallographer's Guide to SHELXL; Oxford University

Press: New York, 2006.

(12) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.;

Cheeseman, J. R.; Scalmani, G.; Barone, V.; Mennucci, B.; Petersson, G. A.;

Nakatsuji, H.; Caricato, M.; Li, X.; Hratchian, H. P.; Izmaylov, A. F.; Bloino, J.;

Zheng, G.; Sonnenberg, J. L.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.;

Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Vreven,

T.; Montgomery, J. A., Jr.; Peralta, J. E.; Ogliaro, F.; Bearpark, M.; Heyd, J. J.;

Brothers, E.; Kudin, K. N.; Staroverov, V. N.; Kobayashi, R.; Normand, J.;

Raghavachari, K.; Rendell, A.; Burant, J. C.; Iyengar, S. S.; Tomasi, J.; Cossi, M.;

Rega, N.; Millam, M. J.; Klene, M.; Knox, J. E.; Cross, J. B.; Bakken, V.; Adamo,

C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.; Cammi,

R.; Pomelli, C.; Ochterski, J. W.; Martin, R. L.; Morokuma, K.; Zakrzewski, V. G.;

Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Dapprich, S.; Daniels, A. D.; Farkas,

O.; Foresman, J. B.; Ortiz, J. V.; Cioslowski, J.; Fox, D. J. Gaussian 09, Revision

D.01; Gaussian, Inc.: Wallingford, CT, 2013.

(13) Rahalkar, A.; Stanger, A. “Aroma”. This software may be downloaded from

http://schulich.technion.ac.il/Amnon_Stanger.htm

(14) (a) NICS-Scan: Stanger, A. J. Org. Chem. 2006, 71, 883. (b) σ-only model: Stanger,

A. J. Org. Chem. 2010, 75, 2281. All the NICSπ,ZZ that are reported here are

obtained from NICS-scan and the σ-only model. (c) NICS-XY-Scan: Gershoni-

Poranne, R.; Stanger, A. Chem. Eur. J. 2014, 20, 5673.

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8. NMR Spectra of New Compounds

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