Lanthanum(III) triflate-catalyzed cyclopropanation via intramolecular methylene transfer.
A new method for cyclopropanation involving intramolecular methylene transfer from an epoxide to an olefin has been developed. This La(OTf)(3)-catalyzed process proceeds with good efficiency and with high stereoselectivity. A range of examples illustrating substrate scope are given along with a mechanistic rationale. Also demonstrated is an asymmetric cyclopropane synthesis that combines enantioselective epoxidation with this methylene-transfer protocol.
Hardee
David J
DJ
Department of Chemistry, Columbia University, New York, New York 10027, USA.
Lambert
Tristan H
TH