Lithium bis (dimethylphenylsily1) cuprate (2), in contrast to dialkylcuprates, reacted with a#- unsaturated sulfoxides 1 to give Michael products 3 and 4 in good yields. The E and 2 sulfoxides 1 afforded predominantly 3 and 4, respectively. When the reaction was quenched with deuterium oxide, four a-deuteriated sulfoxides 5-8 were obtained. While the ratio of 5 to 6 was 9010 from (E)-1 and 70: 30 from (2)-1, 7 and 8 were formed in equal amounts ...
