Synthesis and Applications of Highly Stable Non-Symmetrical Heterocyclic Carbenium Ions Cyril...

Synthesis and Applications of Highly Stable Non-Symmetrical Heterocyclic Carbenium Ions

Cyril Nicolas

Group of Prof. Jérôme Lacour

Department of Organic Chemistry

April, 28th 2008

Highly Stable Carbocations

The higher the pKR+ value, the higher the stability of the cation

pKR+ = Hx + log

R3C+ + H2O R3COH + H+

[R3C+]

[R3COH]

KR+

Articles: J. Am. Chem. Soc. 1988, 110, 633 J. Am. Chem. Soc. 1977, 99, 4721 J. Am. Chem. Soc. 1971, 93, 4715 J. Chem. Soc. 1949, 1724

pKR+ = 10

pKR+ = 13

O O

O

pKR+ = 9.1

pKR+ = 4.2

N

pKR+ = 9.75

S

pKR+ = 0.1

O

pKR+ = 1.1

Diffenbach, R. A.

Thame, N. G.

J. C. Martin

Komatsu, K.

Phillips, J. N.

Freedman, H. H

N N

pKR+ = 9.36

N N

N

Malachite Green Crystal Violet

Phillips, J. N.

Phillips, J. N.

O OHO

COOH

Fluoresceine

Laursen, B. W.; Krebs, F. C. Angew. Chem., Int. Ed. 2000, 39, 3432

MeO OMeOMe

OO

OMe

Me

MeN

N

R

RN

R

Y-

180 °C, NMP

RNH2 (excess)

R = Me, nPr, nHex, nOct

Y-

Y- = PF6-, BF4

-

Synthesis

Triazatriangulenium Cations and Derivatives - Synthesis

MeOOMe

O

OMe

O

MeMe

H2N R

MeO OMeOMe

O

OMe

O

MeMe

NH2

R

NR

HMeO N

O

OMe

O

MeMe

R

OMe

-MeOH -H+ -MeOH

MeO N

O

OMe

O

MeMe

R

Y- Y- Y- Y-

c 10-5 M (CH2Cl2)Light absorption Light emission

Triazatriangulenium Cations and Derivatives – Synthesis and Properties

OMe

O O

OMeMeO OMe

Me Me

pKR+ ~ 6.1

OMeN OMeR

O O

Me Me

pKR+ ~ 11

RNH2

rt

RNH2

N

O

N

O

MeMe

RR

pKR+ ~ 19

110 °C

RNH2

NNRR

N

R

pKR+ ~ 24

180 °C

J. Am. Chem. Soc. 1983, 105, 2889

Ito

J. Org. Chem. 1999, 64, 5815

Triazatriangulenium Cations and Derivatives – Stability

OMe

O O

OMeMeO OMe

Me Me

pKR+ ~ 6.1

OMeN OMeR

O O

Me Me

pKR+ ~ 11

RNH2

rt

RNH2

N

O

N

O

MeMe

RR

pKR+ ~ 19

110 °C

RNH2

NNRR

N

R

pKR+ ~ 24

180 °C

C2-Symmetric [4]Helicenium - Synthesis and Configurational Stability

Synthesis

PF6-

MeO OMeOMe

O

OMe

O

MeMe PF6-

N

O

N

O

MeMe

RR

110 °C, NMP

RNH2 (excess)

R = Me, nPr

pkR+ ~ 19

O

NN

O

nPrnPr

M-Enantiomer

X-ray : R = Pr

O

N N

O

nPrnPr

P-EnantiomerFrom the X-ray of

Laursen, B. W. and Krebs, F. C.


Synthesis

PF6-

MeO OMeOMe

O

OMe

O

MeMe PF6-

N

O

N

O

MeMe

RR

110 °C, NMP

RNH2 (excess)

R = Me, nPr

pkR+ ~ 19

Angew. Chem. Int. Ed. 2003, 42, 3162

Resolution process: Ion pairing with enantiopure BINPHAT anion

PO

O

OO

ClCl

Cl

Cl

Cl

ClCl

Cl

O

O

From (R)-BINOL

()-BINPHAT

d.e. > 96%

Me2NH2

Ph.D thesis A. Londez, 2000.

O

NN

O

nPrnPr

Ph.D thesis C. Herse, 2003.

Org. Lett. 2000, 2, 4185

Configuration assignment (VCD spectroscopy)

Angew. Chem. Int. Ed. 2003, 42, 3162

t1/2 = 13.4 min (196 °C)

154.3 kJ.mol-165-67 kJ.mol-1t1/2 = 1 h (57 °C)

98 kJ.mol-1

Hellwinkel, Martin

65-67 kJ.mol-1t1/2 = 1 h (57 °C)

98 kJ.mol-1

Hellwinkel, Martin

Hellwinkel, Martin


Synthesis

PF6-

MeO OMeOMe

O

OMe

O

MeMe PF6-

N

O

N

O

MeMe

RR

110 °C, NMP

RNH2 (excess)

R = Me, nPr

pkR+ ~ 19

Racemization Barrier (determined using CSP-HPLC after derivatization into neutral adducts)

Addition adducts

X

O

NN

O

RR

R-M

O

NN

O

RR

R

R = CH3, CH2CN, CH2SO2R, CH2S(O)pTol*

Addition adducts – New Resolution Method

50

-50

0

400250 300 350

[nm]

---

(M)

[]D=-650

c = 0.1, CH2Cl2

1

CD (CH2Cl2, 10-5 M)X-ray

1

O

NN

O

iPriPr

S

O

p-Tol

(R)

racemic

O

NN

O

RR

R = nPr, iPr, nOct, cHex, ...

MeS

p-Tol

O

(R)

(SiO2, Et2O)

LDA O

NN

O

RR

S

O

p-Tol

(R)

1:1 mixture of diastereomers78-88% yield

Scaled-up to 10 mmol of cation (5g)

THF, 0 °C

R = nPr

Sulfoxides

Angew. Chem. Int. Ed. 2005, 44, 1879Ph.D thesis B. Laleu, 2006

[]D=+830

c = 0.1, CH2Cl2

2

(P)

50

-50

0

400250 300 350

[nm]

---

(M)

CD (CH2Cl2, 10-5 M)X-ray

racemic

O

NN

O

RR


MeS

p-Tol

O

(R)

LDA O

NN

O

RR

S

O

p-Tol

(R)



THF, 0 °C

Sulfoxides(SiO2, Et2O)

1

R = nPr

2

O

N N

O

iPriPr

S

O

p-Tol

(R)



[]D=-650

c = 0.1, CH2Cl2

1

racemic

O

NN

O

RR


MeS

p-Tol

O

(R)

LDA O

NN

O

RR

S

O

p-Tol

(R)



THF, 0 °C


1

R = nPr

2

O

NN

O

RR

S

O

p-Tol

(R)

E+

(M)O

NN

O

RR

S

EO

p-TolH

O

NN

O

RR

S

p-Tol



[]D=-650

c = 0.1, CH2Cl2

1

Pummerer rearrangement

racemic

O

NN

O

RR


MeS

p-Tol

O

(R)

LDA O

NN

O

RR

S

O

p-Tol

(R)



THF, 0 °C


1

R = nPr

2

O

NN

O

RR

S

O

p-Tol

(R)

E+

(M)O

NN

O

RR

S

EO

p-TolH

O

NN

O

RR

S

p-Tol



[]D=-650

c = 0.1, CH2Cl2

1

Pummerer rearrangement

racemic

O

NN

O

RR


MeS

p-Tol

O

(R)

LDA O

NN

O

RR

S

O

p-Tol

(R)



THF, 0 °C


1

R = nPr

2

O

NN

O

RR

S

O

p-Tol

(R)

E+

(M)O

NN

O

RR

S

EO

p-TolH

O

NN

O

RR

S

p-Tol



[]D=-650

c = 0.1, CH2Cl2

1

Pummerer fragmentation

racemic

O

NN

O

RR


MeS

p-Tol

O

(R)

LDA O

NN

O

RR

S

O

p-Tol

(R)



THF, 0 °C


1

R = nPr

2

O

NN

O

RR

S

O

p-Tol

(R)

E+

O

NN

O

RR

S

EO

p-TolH

97%

(M)O

NN

O

RR



-50

0

50

100

235 335 435 535 635

0

25

50

75

CD / UV

x

103

(M -1

·cm

-1)

(

M -1

·cm

-1)

PF6-

O

N N

O

iPriPr

e.e. > 96%

[ ]365 = + 10200 (c = 5.7•10-3, CH2Cl2)[ ]435 = + 7600 (c = 5.7•10-3, CH2Cl2)

PF6-

O

NN

O

iPriPr

e.e. > 96%

[ ]365 = - 10000 (c = 5.7•10-3, CH2Cl2)[ ]435 = - 7300 (c = 5.7•10-3, CH2Cl2)


1

2

3

4

(SiO2, Et2O)

Ratio: 30, 21.5, 35, 13.5%

35%

30%

21.5%

13.5%

Me

S

O

pTol(R)

LDA

THF, 0 °C, 76%

110 °C, NMP

nPrNH2 (excess)

90 min, 65%

OMeN OMePh

O O

Me Me

pKR+ ~ 11

BF4-

110 °C, NMP

PhNH2 (excess)

90 min, 95%

OMe

O O

OMeMeO OMe

Me Me

pKR+ ~ 6.1

BF4-

N

O

N

O

MeMe

nPrPh

pKR+ ~ 19

BF4-


Ph.D thesis B. Laleu, 2006

O

(R)NN

O

Ph

S

O

pTol(R)

O

(S)NN

O

nPrPh

O

SpTol

(R)

nPr

(M) (M)1 2

O

(S)N N

O

PhnPr

O

(R)N N

O

PhnPr

S

O

pTol(R) S

O

pTol(R)

(P)(P)3 4

Test reactions

Triazatriangulenium Cations: Highly Stable Carbocations for Phase-transfer Catalysis

BF4-

180 °C, NMP

MeO OMeOMe

O

OMe

O

MeMe

RNH2 (excess)N N

N

R R

RBF4

-

pkR+ ~ 24

R = (CH2)2OH, nPr, nHex,nOct

Synthesis of Triazatriangulenium salts

T+

~ 45%

-Ketoester alkylation

Aziridination of styrene

Epoxidation of trans-chalcone

Addition of Dichlorocarbene to Styrene

Org. Lett. 2006, 8, 4343

Is it possible to use them as phase-transfer catalyst (PTC) ?

Test reactions


BF4-

180 °C, NMP

MeO OMeOMe

O

OMe

O

MeMe

RNH2 (excess)N N

N

R R

RBF4

-

pkR+ ~ 24



T+

~ 45%





O

CO2Me

catalyst (mol %)PhCH2Br

OCO2Me

Ph50% KOH aq, 20 °CCH2Cl2

entry catalyst yield (%)amol %

1

432

567

time (h)

55R = n-prop65

R = n-oct

0TBABb

R = n-hex

50R = (CH2)2OH

85

19 011

111

none

101010

1010

95c3 5R = n-oct

aYield measured by 1H-NMR spectroscopy using mesit--ylene as internal reference. b TBAB = [N+(nBu)4]Br-.c85% isolated yield.

-

Org. Lett. 2006, 8, 4343

Test reactions


BF4-

180 °C, NMP

MeO OMeOMe

O

OMe

O

MeMe

RNH2 (excess)N N

N

R R

RBF4

-

pkR+ ~ 24



T+

~ 45%





Org. Lett. 2006, 8, 4343

Ph Ph

Ocatalyst (10 mol %)

30% H2O2

Ph Ph

OO

50% KOH aq Triton X-100 (1 mol %)

iPr2O, 20 °C

aConversion determined by HPLC analysis (Nucleosil 50-5,hexane : iPrOH 99:1, 0.5 mL·min-1, 23 °C, 230 nm); bIsolatedyields after chromatography (SiO2, hexane : EtOAc 9:1, Rf 0.22).

catalyst yield (%)bconversion (%)a

time (h)

no 18 0 0TBAB 17 45 35

162117R = (CH2)2OH232717R = n-prop222617R = n-hex445017R = n-oct


BF4-

180 °C, NMP

MeO OMeOMe

O

OMe

O

MeMe

RNH2 (excess)N N

N

R R

RBF4

-

pkR+ ~ 24



T+

~ 45%

Org. Lett. 2006, 8, 4343

Ph PhCl

ClCHCl3, KOH powder

catalyst (2 mol %)CH2Cl2, 40 °C, 6 h

catalyst yield (%)aconversion (%)a

equiv. CHCl3 / KOH

no 5 12 10TBAB 5 100 100

16165R = (CH2)2OH27285R = n-prop27275R = n-hex26265R = n-oct

18-C-6 5 100 >95c

182020no68d7020R = n-oct

aConversions and yields determined by 1H-NMR using mesityleneas internal reference. c 90% isolated yield obtained by distillation on a 10 mmol scale of styrene. d 65% isolated yield obtained bydistillation on a 10 mmol scale of styrene.

Test reactions


BF4-

180 °C, NMP

MeO OMeOMe

O

OMe

O

MeMe

RNH2 (excess)N N

N

R R

RBF4

-

pkR+ ~ 24



T+

~ 45%





Org. Lett. 2006, 8, 4343

Ph + MeS

O

O

NCl

Na Ph

N

Tscatalyst (10 mol %)

CH2Cl2 : H2OI2, 20 °C

entry catalyst yield (%)bconversion (%)a

1

432

9 7232816

567

20

8

573037

R = n-propR = n-hexR = n-oct

R = (CH2)2OHTBAB

no 35

aConversion was determined by HPLC analysis (Nucleosil 50-5,hexane, 0.5 mL·min-1, 23 °C, 254 nm; tR: 6.19 min (styrene), 7.99 min (phenanthrene)). bYield of isolated product after columnchromatography (SiO2, hexane : EtOAc 9:1, Rf 0.26)

time (h)

555

5524

R = n-hex 24 82~1008095TBAB 15

O

CO2MePhCH2Br (1.2eq)

OCO2Me

Ph50% KOHaq, 25 °C

entry catalyst yield (%)atemperature°C

1

54

2

0

678

25

time (h)

none

75[1][BF4]

~10025rac-[2][BF4]

TBAB

25 60rac-[2][BF4]

2525 85

1.5 551.51.51.51.5

19

1.5 531.5 28

25250

M-[2][BF4]

M-[2][BF4]P-[2][BF4]

aYield measured by 1H-NMR spectroscopy using mesitylene as internalreference.bThe enantiomeric excesses were determined by CSP-HPLC (Chiralpak-IB DAICEL, 0.5 ml.min-1, hexane/iPrOH 95:5, 23 °C, 254.4 nm.

ee (%)bmol %

-

1010102.72.72.72.7

-

----000

3

[1][BF4]

Phase-Transfer Catalysis with Enantiopure C2-Symmetric [4]Helicenium Ions

(M)-[3][BF4](P)-[3][BF4]

O

CO2MePhCH2Br (1.2eq)

OCO2Me

Ph50% KOHaq, 25 °C

entry catalyst yield (%)atemperature°C

1

2

time (h)

(rac)-[3][BF4] -5 17

2.2 20

2.2

2.2 20

-5

-5

(M)-[3][BF4]

(P)-[3][BF4]

aYield measured by 1H-NMR spectroscopy using mesitylene as internal reference. cTheenantiomeric excesses were determined by CSP-HPLC (Chiralpak-IB DAICEL, 0.5 ml.min-1, hexane:iPrOH 95:5, 23 °C, 254.4 nm.

ee (%)bmol %

2.7

2.7

2.7

0

0

03

Phase-Transfer Catalysis with Non-Symmetrical [4]Helicenium Ions

Geodesic Polyarenes and Carbon Nanotubes

O

O

X

(f,sC)-C76-D2

Diederich, F.

Agranat , Curl, Dresselhaus, Haddon, Hirsch, Kroto, Mehta,

Paquette, Prakash, Rabideau,

Scott, Siegel, Smalley

C60

OO

OMe

X

X

X

OO

OMe

X

XX

Siegel, J.

J. Org. Chem. 1992, 57, 61

MeMe

Me

Me

Me

Me

D3

Ar

Ar

Ar

Ar

Ar

N

N

Siegel, J.

Mascal, M.

Galow, T. H

Rabideau, P. W

J. Am. Chem. Soc. 2007, 129, 13193

J. Org. Chem. 2007, 72, 4323

J. Am. Chem. Soc. 2007, 128, 6870

J. Am. Chem. Soc. 1995, 117, 6410

Reviews: Chem. Rev. 2006, 106, 5049 Chem. Rev. 2006, 106, 4843 Chirality 2005, 17, 404 Chem. Rev. 2006, 106, 4868 Tetrahedron 1998, 54, 13325

Trioxatricornan – a Chiral Cup-Like Molecule

OO

O

O O

OMeLi

(R)

R'M

ZY

X

Y Z

XR'

(R)

X, Y, Z = NR or O

Synthesis and Resolution of a Chiral Cup-Like Molecule

OMe

O O

OMeMeO OMe

N

O

N

O

MeMe

PrPh

OMeN OMePh

O OMeMe MeMe

NNPrPh

O

NN

O

Ph PrN N

O

PhPr

MeLi, THF

0 °C, 16 h, 97%

NH2

110 °C, 1.5 h

95%

nPrNH2, NMP

120 °C, 2 h, 65%

LiI, NMP, 64%

180 °C, 1.5 h

(S) (R)

Synthesis


Inte

nsity

(ar

b un

its)

time (min)

Chromatographic Resolution

Daicel OJ-H (99.5/0.5 hex / i-PrOH), 0.5 mL/minIn collaboration with E. Francotte (Novartis)

17.2 min

30.8 min[]589 = +16.1 ± 1.4 (c = 1 mg / 1 mL)

[]589 = -13.2 ± 1.6 (c = 1 mg / 1 mL)

(R) Enantiomer (S) EnantiomerN N

O

PhPr

(R)NN

O

Ph Pr

(S)

ECD Spectra

First eluted fraction(dextrogyre)

-5

0

5

400300 350Wavelength[nm]

C = 4 10-5 mol.l-1

Second eluted fraction(levogyre)


VCD spectra

Wavenumber / cm -112001300140015001600

A

-1.5e-5

-1.0e-5

-5.0e-6

0.0

5.0e-6

1.0e-5

1.5e-5

ECD Spectra

First eluted fraction(dextrogyre)

-5

0

5

400300 350Wavelength[nm]

C = 4 10-5 mol.l-1

Second eluted fraction(levogyre)

First eluted fraction (dextrogyre)

Second eluted fraction (levogyre)


O

PhPr

(R)NN

O

Ph Pr

(S)


In collaboration with T. Bürgi (Neuchâtel)

(S) Enantiomer


1, 2.91 kcal/mol 2, 2.86 kcal/mol 3, 0.0 kcal/mol

4, 1.70 kcal/mol

6, 2.30 kcal/mol

8, 1.66 kcal/mol 9, 2.20 kcal/mol

5, not stable

7, not stable

DFT (b3pw91, 6-31++G(d,p))

possible conformers of enantiomer (S)


NN

O

Pr

(S)

NN

O

Ph Pr

(S)


DFT (b3pw91, 6-31++G(d,p))

IR spectrum




5, not stable

7, not stable

(S) Enantiomer

VCD spectrum

(S)-conformer 3

Wavenumber / cm-1

12001300140015001600

Boltzmannaverage

DFT (b3pw91, 6-31++G(d,p))

85%

Wavenumber / cm-1

12001300140015001600

Boltzmann average

conformer 3

conformer 3


IR spectrum Calculated structure (S enantiomer)




5, not stable

7, not stable

DFT (b3pw91, 6-31++G(d,p))

In collaboration with T. Bürgi (Neuchatel)

exp

From Second eluted (levogyre) fraction

Conformer 3A

0.0

0.5

1.0

1.5

2.0

12

3

3

4

4

5

5

6

6

7

7

8

9

10

11

12

10

13

13

14

15

16

14

16

18

18

17

17

12

19

911

12

20

21

22

23

19

20

2122

23

Wavenumber / cm-1

12001300140015001600

A

0.0

0.5

1.0

1.5

2.0

12

3

3

4

4

5

5

6

6

7

7

8

9

10

11

12

10

13

13

14

15

16

14

16

18

18

17

17

12

19

911

12

20

21

22

23

19

20

2122

23

Wavenumber / cm-1

12001300140015001600


O

PhPr

(R)NN

O

Ph Pr

(S)


VCD spectrum

DFT (b3pw91, 6-31++G(d,p))


Calculated structure (S enantiomer)From Second eluted

(levogyre) fraction

Wavenumber / cm-1

12001300140015001600

A

0

2e-5

4e-5

12

3

345

6

7

9

10

11

1314

15

16

17

18

19

2123

22

9

1245

6

7

10

13

16

1721

2219

1245

6

7

10

13

16

1721

2219

Wavenumber / cm-1

1400

-5

4e 5

12

3

345

6

7

9

10

11

1314

15

16

17

18

19

2123

22

9

1245

6

7

10

13

16

1721

2219

1245

6

7

10

13

16

1721

2219

1245

6

7

10

13

16

1721

2219

1245

6

7

10

13

16

1721

2219

exp

Conformer 3




5, not stable

7, not stable


O

PhPr

(R)NN

O

Ph Pr

(S)


(S) Enantiomer; []365 = -300 (c = 0.06 g / 100 mL)

VCD spectrum

DFT (b3pw91, 6-31++G(d,p))


Calculated structure (S enantiomer)From Second eluted

(levogyre) fraction

Wavenumber / cm-1

12001300140015001600

A

0

2e-5

4e-5

12

3

345

6

7

9

10

11

1314

15

16

17

18

19

2123

22

9

1245

6

7

10

13

16

1721

2219

1245

6

7

10

13

16

1721

2219

Wavenumber / cm-1

1400

-5

4e 5

12

3

345

6

7

9

10

11

1314

15

16

17

18

19

2123

22

9

1245

6

7

10

13

16

1721

2219

1245

6

7

10

13

16

1721

2219

1245

6

7

10

13

16

1721

2219

1245

6

7

10

13

16

1721

2219

exp




5, not stable

7, not stable

NN

O

Ph Pr

(S)

[]589 = -13.2 ± 1.6 (c = 1 mg / 1 mL)

Conformer 3


What has been achieved

TRIAZATRIANGULENIUM CATIONS

Synthesis: Facile Highly Stable Toward Reactive Bases and

Nucleophiles. Efficient Phase-Transfer Catalysts

CHIRAL CUP-LIKE MOLECULES

Synthesis: Straightforward, Versatile Easy Separation of the Enantiomers by

Preparative CSP-HPLC Determination of the Absolute configuration

by VCD Measurements1, 2.91 kcal/mol 2, 2.86 kcal/mol 3, 0.0 kcal/mol



5, not stable

7, not stable

Acknowledgments

Prof. Alexandre Alexakis and Bo. W. Laursen

Prof. Jérôme Lacour

Dr. Gérald Bernardinelli (X-Ray Structures)

Dr. Damien Jeannerat, André Pinto, Jean-Paul Saulnier, Bruno Vitorge (NMR)

Prof. Thomas Bürgi (DFT calculations)

Dr Eric Francotte (HPLC analyses)

Prof. Rainer Herges, Olaf Magnussen (Nanoparticles)

Prof. Robert Deschenaux, Stéphane Frein (Liquid Crystals)

Alexandre Fürstenberg, Prof. Eric Vauthey (DNA Intercalation)

Sandrine Perrothon, Benjamin Elias, Thomas Frossard

Members of the Lacour’s group (past and present)

Christelle Herse

Benoît Laleu

Dr. Pierre Mobian

Members of the Department of Organic Chemistry

Acknowledgments

Nathalie Mehanna (Lacour group)

Mylene Cargouet

Swiss National Science Foundation (SNSF)

Département de l’Instruction Publique (DIP)

Société Académique de Genève

My family, my wife, my two children

Schlegel diagrams

vertice

edges Euler's formula: f+v = e+2

Thilgen, C.; Diederich, F. Chem. Rev. 2006, 106, 5049

1

2

3

4

(SiO2, Et2O)

Ratio: 30, 21.5, 35, 13.5%

35%

30%

21.5%

13.5%

Me

S

O

pTol(R)

LDA

THF, 0 °C, 76%

110 °C, NMP

nPrNH2 (excess)

90 min, 65%

OMeN OMePh

O O

Me Me

pKR+ ~ 11

BF4-

110 °C, NMP

PhNH2 (excess)

90 min, 95%

OMe

O O

OMeMeO OMe

Me Me

pKR+ ~ 6.1

BF4-

N

O

N

O

MeMe

nPrPh

pKR+ ~ 19

BF4-

O

(R)NN

O

Ph

S

O

pTol(R)

O

(S)NN

O

nPrPh

O

SpTol

(R)

nPr

(M) (M)

O

(S)N N

O

PhnPr

O

(R)N N

O

PhnPr

S

O

pTol(R) S

O

pTol(R)

(P)(P)


Ph.D thesis B. Laleu, 2006

-80

-60

-40

-20

20

40

60

330 430 530 630 730

0

(

M -1

·cm

-1)

[ ]D = - 430 (c = 0.06, CH2Cl2)

[ ]D = + 680 (c = 0.06, CH2Cl2)

[ ]D = - 450 (c = 0.06, CH2Cl2)

[ ]D = + 590 (c = 0.06, CH2Cl2)

4

12

3

(M)

(P)

Ratio: 30, 21.5, 35, 13.5%

1

2

3

4

(SiO2, Et2O)

35%

30%

21.5%

13.5%

CD (CH2Cl2 ,10-5 M)

Wavelenght (nm)


Ratio: 30, 21.5, 35, 13.5%

1

2

3

4

(SiO2, Et2O)

35%

30%

21.5%

13.5%

1 2

10-5 M, CH2Cl2

(

M -1

·cm

-1)

-75

-25

25

75

230 330 430 530 630 730

Wavelenght (nm)

50

100

x

103

(M -1

·cm

-1)

0

CD / UV

[ ]435 = - 4600 (c = 0. 6; CH2Cl2)

O

(R)NN

O

Ph

S

O

pTol(R)

O

(S)NN

O

nPrPh

O

SpTol

(R)

nPr HBF4 aq. (30.0 eq.)

(-)-(R,R,M)

Acetone, rt, 6h

(-)-(R,S,M)

+

(M) (M)


Ratio: 30, 21.5, 35, 13.5%

1

2

3

4

(SiO2, Et2O)

35%

30%

21.5%

13.5%

10-5 M, CH2Cl2

(

M -1

·cm

-1)

-75

-25

25

75

230 330 430 530 630 730

Wavelenght (nm)

50

100

x

103

(M -1

·cm

-1)

0

CD / UV

4 3(-)-(R,R,P) (-)-(R,S,P)

+O

(S)N N

O

Ph nPr

S

O

pTol(R)

(P)O

(R)N N

O

nPr Ph

S

O

pTol(R)

(P)

HBF4 aq. (30.0 eq.)

Acetone, rt, 6hO

N N

O

Ph nPr

(P)

e.e. > 98%

[ ]435 = + 4800 (c = 0. 6; CH2Cl2)


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Synthesis and Applications of Highly Stable Non-Symmetrical Heterocyclic Carbenium Ions Cyril...

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