Trisubstituted cyclopropanes 5a-f are prepared by carhene addition to the appropriate olefins. While 5a (Y= OAc) and 5c (Y= Cl) rearrange in the presence of BuLi, 5d (Y= SPh) is stable enough to allow the envisaged sequence for triafulvene (Scheme 2): halogen-Li exchange, followed by methylation of 6d, gives 7d in a 93 YO yield; after base-induced elimination of HBr from 7d, the key precursor l-methylene-2-(phenylthio) cyclopropane (9, ...
