Felkin-Anh

Prévia do material em texto

L
MS
O
Nu-
Anti-Felkin
L
MS
OR
Nu-
Felkin
103°
R
L
MS R
HO
Nu
L
MS OH
R
Nu
Felkin-product anti-Felkin-product
L
O
R
MS nucleophile
L
Nu
MS
OHR
L
Nu
MS
RHO
Cram or
Felkin-Anh
Anti-Cram or
Cram Chelate
S = Small 
M = Medium
L = Large
The Felkin Anh Model 
Chem. Rev. 1999, 99, 1199 
The Cram Chelate Model 
L
O
R
MS nucleophile
L
Nu
MS
OHR
L
Nu
MS
RHO
1 2 3
Cram or
Felkin-Anh
Anti-Cram or
Cram Chelate
S = Small 
M = Medium
L = Large
OR
Met
L
M
S
Nu-
L
M
S
R
Nu
OH
anti-Felkin-product
L = OR', NHR',...
L
M
L
M
Nu
OH
L
M
Nu
HOO
R
2) H+
1) M Nu
Entry FA : CC
Ph
Felkin-Anh (FA) Cram-Chelat (CC)
1
M Nu
71 : 29
Ph2 79 : 21
RR
3 tBuMgBr 98 : 02
Ph4 86 : 14
Ph5 90 : 10
Ph6 87 : 13
Et
iPr
Ph
Ph7
S S S
98 : 02tBu
Ph
8 75 : 25Ph
9 80 : 20
Ph10 43 : 57
Bu
Ph11 50 : 50Ph
OSiMe2tBu c-C6H1112 95 : 05SnBu3
ML
CH3 MeMgBr
CH3 PhMgBr
CH3
R
H
H
H
CH3 MeMgBr
CH3 MeMgBr
CH3 MeMgBr
CH3 MeMgBr
S
H
H
H
H
H
H
H
Cl CH3 LiAlH4
Cl C2H5 NaBH4
Cl LiAlH4CH3
Cl LiAlH4
H
H
H
H
HH BF3
The Felkin Anh Model 
The Felkin Anh Model 
L
M
L
M
Nu
OH
L
M
Nu
HOO
R
2) H+
1) M Nu
Entry FA : CC
Felkin-Anh (FA) Cram-Chelat (CC)
M Nu
RR
S S S
ML RS
Ph19 17 : 83p-Tol
Ph20 02 : 98
Ph21 04 : 96
p-Tol
Ph22 12 : 88Ph
Ph23 34 : 66Ph
NBn2 Me13 95 : 05
NBn2 Me14 06 : 94
24 23 : 77Ph
SMe Et15 Li(sBu)3BH 99 : 01Ph
CO2Me Me17 73 : 27Ph
Me18 03 : 97Ph
SMe Et16 06 : 94Ph
H LiAlH4
H PhMgBr
H PhMgBrCH3
CH3 PhLi
OH
OH
OH
OH
CH3 MeMgBrOH
CH3MgBrHH
CH3TiCl3HH
CH3 H NaBH4NHAc
H
KBH4H
CO2Me Zn(BH4)2H
Zn(BH4)2H
Felkin-Anh or Cram Chelate? 
O O
H
O
O O
Nu
OH
O O
Nu
OH
+
Felkin-product anti-Felkin-product
nucleophile
L=O...
M=CH2O...
nucleophile FA:CC 
allylMgBr 60:40 
allylTi(OiPr)3 71:29 
(allyl)2Zn 90:10 
PhLi 48:52 
PhMgBr 48:52 
PhTi(OiPr)3 09:91 
MeLi 60:40 
MeMgBr 67:33 
nBuLi 69:31 
nBuMgBr 75:25 
iBuMgBr 75:25 
nBuTi(OiPr)3 90:10 
Li 50:50 
Li 50:50 
Li CH(OEt)2
 
70:30 
S S
Ph Li , Ti(OiPr)4 
70:30 
S S
Ph Li , Zr(OiPr)4 
78:22 
S S
Ph Li , ZnBr2 
55:45 
S S
Ph Li , MgBr2 
47:53 
B(OiPr)2 
92:08