Discrimination of diastereotopic sulfonyl oxygens by intramolecular hydrogen bonding: Stereoselective hydrogenation of α-sulfonyl radicals
作者:Nobuyuki Mase、Yoshihiko Watanabe、Takeshi Toru
DOI:10.1016/s0040-4039(99)00297-x
日期:1999.4
Stereoselective intramolecularhydrogenbonding between the hydroxy group and a stereogenic sulfonyl oxygen led to high diastereoselectivity in the radical reaction of α-(1-hydroxyethyl)vinyl sulfone with alkyl iodides and tributyltin hydride in the presence of triethylborane as a radical initiator. Intramolecularhydrogenbonding was demonstrated to play an important role in controlling the diastereoselectivity
(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