Preparation of some novel butyl, butenyl, butadienyl and butynyl sulfone electrophiles for use in enolate trapping studies

The preparation of some novel four-carbon electrophiles and electrophile intermediates is described. Thus, the chlorobutenyl sulfone (5), the iodobutynyl sulfone (6) and the hitherto unreported chlorobutynyl sulfone (4) were prepared. The novel intermediates, containing a chelating imidazolyl functionality, the N- methylimidazolyl sulfides (13)-(15) were also prepared. However, they polmerized rapidly, thus preventing further synthetic manipulations. The preparation of the α-(trimethylsilyl) butadienyl sulfones (17) and (18) is described and the mode of formation of the intermediate α- trimethylsilyl sulfides (21) and (22) from the trimethylsilylbutenyl sulfide (27) is discussed.