Stereoselective Reactions of Vinylenedisulfonium Salts

Abstract

To a suspension of (2a) (20.7g, 0.14mol) in anhydrous dichloromethane (100 ml) is added ( 1 a) (10.4 g, 0.07 mol) under nitrogen, and the mixture is warmed (bath temperature 50°C) for 3 h in the absence of moisture. After cooling the crystals are filtered off and recrystallized from anhydrous methanol; 17.4g (70'x) of colorless crystals of m. p. 117--119"C (dec.) is obtained. truns-S.S'-Dirthq~/-S,S'-tlie~/~y/~inq~lei~ed~su/~oniut~~ bisitetruf'luoroborute) ( 4 e j / ( 4 e t )Analogous reaction of (2a) (1.20g, 8.1mmol) and ( 3 e ) (2.00g, 8.0 mmol) in anhydroiis dichloromethane (40 ml) for 3 h at 50°C affords 2.46g (85 "/o) of colorless crystals of m. p. 161-162°C (dec.).