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.
Catalytic Asymmetric Cyclopropanation of Allylic Alcohols with Titanium-TADDOLate: Scope of the Cyclopropanation Reaction
作者:André B. Charette、Carmela Molinaro、Christian Brochu
DOI:10.1021/ja0108382
日期:2001.12.1
titanium-TADDOLate complex was effective at catalyzing the cyclopropanation reaction of allylicalcohols in the presence 1 equiv of bis(iodomethyl)zinc. After initial optimization of the catalyst structure, excellent yields and enantiomeric ratios were obtained for 3-aryl- or 3-heteroaryl-substituted allylicalcohols (up to 97:3). Alkyl-substituted allylicalcohols gave modest yields and enantiomeric ratios (up
High-Diastereoselective and Enantioselective Cyclopropanation of α,β-Unsaturated Fischer Carbene Complexes: Synthesis of Chiral 1,2-Disubstituted and 1,2,3-Trisubstituted Cyclopropanes
作者:José Barluenga、Pablo L. Bernad、José M. Concellón、Alejandro Piñera-Nicolás and、Santiago García-Granda
DOI:10.1021/jo9708708
日期:1997.10.1
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.