Synthesis and Trapping of Some Reactive Cyclopropenes

Abstract

Commencing with 1,1,2-tribromo-2-trimethylsilylcyclopropane (1d), 1,2- dibromo -and 1-bromo-2-trimethylsilyl-cyclopropene (2d) and (6) are easily prepared. These reactive cyclopropenes decompose on standing at ambient temperature but can be trapped in situ as Diels-Alder adducts (4) and (5). Furthermore, 1,2-bis( trimethylsilyl )- and 1- trimethylsilyl-cyclopropene (8) and (9) can be prepared from cyclopropane (1d) via the bromo - and lithio-trimethylsilylcyclopropenes (6) and (7) in a 'one-pot' procedure and trapped as adducts (4e,f) respectively.