Massachusetts Institute of Technology
Organic Chemistry 5.512
March 30, 2005
Prof. Rick L. Danheiser
Unit 2
Stereocontrolled Alkylation
and Related Electrophilic Substitution Strategies
V. Catalytic Methods




α-Oxidation of Aldehydes and Ketones (H. Yamamoto, MacMillan, Zhong, Y. Hayashi)
Alkylation of Imine Derivatives of α-Amino Esters (O'Donnell, Corey, Maruoka)
Tsuji Allylation of Ketones (Stoltz, Trost)
Enantioselective Protonation Strategies (Fu)
Photograph removed due to copyright reasons
Special Issue on
Asymmetric Organocatalysis
Accts. Chem. Res. 2004, 37, 487-631
Enantioselective
Organocatalytic
Oxidation of Aldehydes with
Nitrosobenzene
Photograph removed due to copyright reasons
"Asymmetric Organocatalysis"
A. Berkessel and H. Gröger
Wiley-VCH, 2005
Photograph removed due to copyright reasons
Alkylation of Imine Derivatives of α-Amino Esters
Martin J. O'Donnell
IUIPUI
Enantioselective Tsuji Allylation
D. C. Behenna; B. M. Stoltz J. Am. Chem. Soc. 2004, 126, 15,044
B. M. Trost; J. Xu J. Am. Chem. Soc. 2005, 127, 2846
O
O
O
6.25 mol% ligand
2.5 mol% Pd2(dba)3
THF, rt
O
85%, 88% ee
O
PPh2 N
(S)-t-Bu-PHOX
Enantioselective Addition of Amines to Ketenes Catalyzed by a Planar-Chiral Derivative
B. L. Hodous; G. C. Fu J. Am. Chem. Soc. 2002, 124, 10,006
NC
O
C
2% (–)-1
R
NH
N
O
NC
R
N
N
toluene, r.t.
Me
Ar
Ar
Fe
Me
Me
Me
up to 98% ee
(–)-1
NC
N
H
O
catalyst*
7
NH
R1
C
NC
R
O
NC
catalyst*
R1
N
H
catalyst*
R
8
O
NC
*
N
H
Me
HO
R
LiOH
H2O2
O
protonation of an achiral enolate
by a chiral Brønsted acid catalyst:
the turnover-limiting and
stereochemistry-determining step?
R1
O
NC
R
88%
NaBH4
Bn
HO
6
84%
N
Ph
Ar
2
MeN
NH
BnOH,
cat. [Et4N]CN
95%
98%
72%
LiAlH(Ot-Bu)3
O
O
i-Pr
BnO
N
Me
4
Et
H
OMe
Ph
3
O
Ph
5
Me