Asymmetric intramolecular michael addition of alpha-sulfinyl vinylic carbanion to enoates.
The first example of an asymmetric intramolecular Michael addition reaction with use of alpha-lithiated vinylic sulfoxide as a Michael donor is reported. Michael addition of the alpha-lithiated vinylic sulfoxide to (Z)-enoates proceeds with high diastereoselectivity to give the adducts with (R)-configuration at the beta-position of the ester in the five-membered-ring formation. The selectivity was reversed in the six-membered-ring formation. The resulting ester enolates were reacted with alkyl halides or benzaldehyde with high diastereoselectivity.
Maezaki
Naoyoshi
N
Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
Sawamoto
Hiroaki
H
Yuyama
Sachiko
S
Yoshigami
Ryoko
R
Suzuki
Tomoko
T
Izumi
Mayuko
M
Ohishi
Hirofumi
H
Tanaka
Tetsuaki
T