Cumulated Trienephosphine Oxides. Bimolecular Trapping of an Alkylidenecyclopropylidene†
journal contributionposted on 26.12.1997, 00:00 by Christiane Santelli-Rouvier, Loïc Toupet, Maurice Santelli
Dihalocarbene addition to allenic phosphine oxides occurs mainly at the allylic double bond. Treatment of dibromocarbene adducts with BuLi leads to cumulated trienephosphine oxides. In some cases, the intermediate alkylidenecyclopropylidene (or its precursor) is exceptionally stabilized, and this carbene (or carbenoid) is trapped by the corresponding cumulated trienephosphine oxide in a bimolecular process. The resultant spiropentane is formed in a regio- and stereoselective manner.