γ-Lactonizations of 2H-chromenes via cyclopropanation
摘要:
A two-step synthesis of tetrahydro-2H-furochromenones from 2H-chromenes is reported. The reaction of a series of tert-butyl 2-diazoacetate derivatives with 2H-chromenes, catalyzed by Rh(2)(OAc)(4), generated cyclopropane intermediates that rearranged to gamma-lactones on treatment with Sn(OTf)(2). (C) 2010 Elsevier Ltd. All rights reserved.
γ-Lactonizations of 2H-chromenes via cyclopropanation
摘要:
A two-step synthesis of tetrahydro-2H-furochromenones from 2H-chromenes is reported. The reaction of a series of tert-butyl 2-diazoacetate derivatives with 2H-chromenes, catalyzed by Rh(2)(OAc)(4), generated cyclopropane intermediates that rearranged to gamma-lactones on treatment with Sn(OTf)(2). (C) 2010 Elsevier Ltd. All rights reserved.