Use of dimethyl sulfate (4 days, 25 OC, CH2C12) in place of methyl fluorosulfonate gave slightly lower yields (ca. 90%). Reaction of vinyl sulfone 5 with optically active vinyllithium reagent 2a2 (Scheme 11) followed by quenching with water provides a 92: s mixture of 1: l adducts 11 and 12.8, 12 Sequential treatment of 5 (28.6 g, 75" 01) with optically active vinyllithium reagent 2a2 (1.1 equiv, THF,-78" C) followed by warming the mixture to-40 OC ...