Diastereoselective radical hydrogenation of alpha-(1-Hydroxyalkyl)vinyl sulfoxides and sulfones controlled by intramolecular hydrogen bonding
The reaction of (S)-alpha-(1-hydroxyalkyl)vinyl sulfoxides (S)-5 with alkyl radicals and tributyltin hydride gave the addition-hydrogenation products with high diastereoselectivity, whereas the reaction with (R)-alpha-(1-hydroxyalkyl)vinyl sulfoxides (R)-5 resulted in complete recovery of the starting sulfoxides. Stereoselective intramolecular hydrogen bonding between the hydroxy group and the diastereotopic sulfonyl oxygen led to high diastereoselectivity in the radical reaction of alpha-(1-hydroxyethyl)vinyl sulfone 12. An important role of intramolecular hydrogen bonding on the diastereoselectivity as well as the reactivity toward alkyl radicals is discussed.
Mase
N
Department of Applied Chemistry, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan, Osaka Gas Co., Ltd., 17 Chuodori-minami-machi, Shimogyou-ku, Kyoto 600-8813, Japan, and Teijinseiki Co., Ltd., 3-2-1 Sakato, Takatsu-k.
Watanabe
Y
Toru
T
Kakumoto
T
Hagiwara
T