Rh2(S-PTAD)4-catalyzed asymmetric cyclopropenation of aryl alkynes
摘要:
Rh-2(S-PTAD)(4) is an effective catalyst for the asymmetric cyclopropenation of aryl alkynes using a siloxyvinyldiazoacetate as the carbenoid precursor. Upon deprotection of the silyl protecting group, highly enantioenriched cyclopropenes bearing geminal acceptor groups can be accessed. These cyclopropenes undergo regioselective rhodium(II)-catalyzed ring expansion to furans. (C) 2011 Elsevier Ltd. All rights reserved.