High-Diastereoselective and Enantioselective Cyclopropanation of α,β-Unsaturated Fischer Carbene Complexes: Synthesis of Chiral 1,2-Disubstituted and 1,2,3-Trisubstituted Cyclopropanes
摘要:
Reaction of chiral vinylcarbene complexes 1 with in situ-generated iodomethyllithium or dibromomethyllithium gives cyclopropylcarbene complexes 4 and 13, respectively, with high diastereoselectivity (de > 91%). Different enantiopure 1,2-disubstituted and 1,2,3-trisubstituted cyclopropanes are obtained starting from chiral carbene complexes 4 and 13, respectively.