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©Kevin Burgess, February 2, 2020 1 Addition Of Water And Alcohols To Aldehydes And Ketones from chapter(s) _____ in the recommended text A. Introduction
©Kevin Burgess, February 2, 2020 1
Addition Of Water And Alcohols To Aldehydes And Ketones from chapter(s) _____ in the recommended text
A. Introduction
©Kevin Burgess, February 2, 2020 2
B. Relative Reactivities Of Aldehydes And Ketones more
ie 120° to 109°. closer thus accentuating
O
1
O
2
O
4
O
3
O
5
most reactive
O
HHH HO
OH
O
H
O
least reactive
H
O OO O
©Kevin Burgess, February 2, 2020 3
C. Proton Transfer Steps common
+H+
-H+
-H+
+H+
HO O+H
HO O +OH OH
+H+
-H+
-H+
+H+
HO N+Me2H
Cl
HO NMe2
Cl
HO+ NMe2
Cl
H
+H+
-H+OO+H2
O+
OH-H+
+H+
HOOH
-H+
+H+
HO O+H +H+
-H+
HO O H2O+ O
©Kevin Burgess, February 2, 2020 4
HO O+H
+H+
-H+
-H+
+H+
HO O H2O+ O
HO O+H
-H+, +H+ -H+, +H+H3N+ OHH2O+ O H2N +OH2
PhPh
-O N+H2
NH2-H+, +H+-H+, +H+ -O N+H2Ph
PhPhHO NH
NH2HO NHPh
HO O+H
-H+, +H+ -H+, +H+H3N+ OHH2O+ O
H2N +OH2
©Kevin Burgess, February 2, 2020 5
D. Addition Of Water equilibrium strongly
Draw the key intermediates for hydration of acetone using curly arrows to show electron flow.
O +H+ H-OH
protonated carbonyl protonated hydrate
+OH
O+H2
OH
-H+
hydrate
-H+
hydrate
OH
OH
O +H+ H-OH
protonated carbonyl protonated hydrate
+OH
O+H2
OH
-H+
hydrate
-H+
hydrate
OH
OH
©Kevin Burgess, February 2, 2020 6
exactly 2 %. 120° to 109° disfavored does
E. Additions Of Alcohols
hemiketal called a hemiacetal.
O +H+ H-OMe
protonated carbonyl protonated hemiketal
+OH
O+HMe
OH
-H+
OMe
OH
©Kevin Burgess, February 2, 2020 7
hemiacetal acetal.
do react
+H+
-H+
-H2O
OH
OMe
O+H2
OMe +OMe
H-OMe
protonated acetal
-H+
+H+O+HMe
OMe
OMe
OMe
O
PhPh
+H+
-H+ PhPhMeOH
-MeOH
+OH
hemiketal
-H+
+H+ PhPhPhPhHO +OMe HO OMe
H
©Kevin Burgess, February 2, 2020 8
+H+
-H+
MeOH
-MeOH
O +OH
-H+
+H+
hemiketal
HO +OMeH
HO OMe
+H+
-H+
MeOH
-MeOH
starting material?
+OHO
-H+
+H+
OMeHO+OMeHOH
©Kevin Burgess, February 2, 2020 9
an alcohol
PhPh
+H+
-H+
-H2O
+H2O
HO OiPr
protonated on OH oxonium ion
PhPhH2O+ OiPr
Ph Ph
+OiPr
+HOiPr
-HOiPr
-H+
+H+ PhPhOiPriPrO
protonated ketal
PhPh
+OiPriPrOH
H2O
protonated on OH oxonium ion
+H+
-H+
-H2O
+H2O
HO OMeH
H2O+ OMeH
+OMe
H
H2O
+HOMe
-HOMe
-H+
+H+
acetalprotonated acetal
H
+OMeMeOH
HOMeMeO
©Kevin Burgess, February 2, 2020 10
+H+
-H+
-H2O
+H2O
protonated on OH oxonium ion
HPhHO OnBu
HPhH2O+ OnBu
Ph H
+OnBu
acetalprotonated acetal
+HOnBu
-HOnBuHPh
nBuO +OnBuH
HPh
nBuO OnBu-H+
+H+
protonated on OH oxonium ion
+H+
-H+
-H2O
+H2O
OEtHOO+Et
acetalprotonated acetal
+HOEt
-HOEt
-H+
+H+
OEtO+Et
HOEtOEt
©Kevin Burgess, February 2, 2020 11
protonated on OH oxonium ion
HO OOH
+H+
-H+
H2O+ OOH
-H2O
+H2OO+
OH
ketalprotonated ketal
O +OH O O+H+
-H+
©Kevin Burgess, February 2, 2020 12
O +H+ H-OMe -H+
protonated carbonyl protonated hemiacetal
+H+
+OH HO +OMeH
+H+
-H+
-H2O H-OMeOHMeO +OH2MeO MeO+
ketalprotonated ketal
+OHMeMeO OMeMeO
©Kevin Burgess, February 2, 2020 13
O+H+
protonated carbonyl protonated hemiketal
+OH HO +OH
OHHO HO
-H+
+H+
HO OOH
+H+
-H+
H2O+O
OH-H2O
O+
OH
protonated ketal ketal
-H+
O +OH O O
©Kevin Burgess, February 2, 2020 14
OEtOH
H+
hemiketal ketal
HO OEt EtO OEt
OMe
OOH
OH
acetalaldehyde + "diol"
H+ H+
OMe
OHOH
+O
MeO
OO
O
O
ketone + "diol" hemiketal
O
OHOH
O+ OHHO
©Kevin Burgess, February 2, 2020 15
to acid is c.
O OH+
ketone + "diol" hemiketal
OHO
HOHO
O
HO
MeO OMe
molecules used to make 3molecules produced 2
molecules used to make 2molecules produced 2
molecules used to make 1molecules produced 2
OO O Oa b c
