Authors: John F. Briones, Huw M.L. Davies
2011, 67, 24, 4313-4317
Rh2(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.