Highly Enantio- and Diastereoselective Tandem Generation of Cyclopropyl Alcohols with up to Four Contiguous Stereocenters

Three highly enantio- and diastereoselective one-pot procedures for the synthesis of cyclopropyl and iodocyclopropyl alcohols with up to four contiguous stereocenters are reported. Route 1 involves asymmetric addition of an alkylzinc reagent to an enal followed by diastereoselective cyclopropanation. Route 2 parallels route 1, except that iodoform is used to generate the zinc carbenoid, and the products are iodocyclopropyl alcohols. Route 3 entails asymmetric vinylation of an aldehyde with divinylzinc reagents and subsequent diastereoselective cyclopropanation.