Highly stereoselective intramolecular Michael addition using alpha-sulfinyl vinyllithium as an unprecedented Michael donor.
[figure: see text] The first example of an asymmetric intramolecular Michael addition reaction using 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 having a stereogenic center with (R)-configuration at the beta-position of the ester in the cyclopentene ring formation. The selectivity was reversed in the six-membered ring formation. On the other hand, the corresponding (E)-enoates provided Michael adducts with poor diastereoselectivity.
Maezaki
N
N
Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
Yuyama
S
S
Sawamoto
H
H
Suzuki
T
T
Izumi
M
M
Tanaka
T
T