Catalytic Decarboxylative sp-sp~3 Coupling

摘要

The majority of C-C bond forming cross-coupling reactions (i.e.,Negishi,Stille,Suzuki-Miyaura,Sonogashira,Kumada) involve three basic transformations:oxidative addition,transmetalation,and reductive elimination.The transmetalation steps in many of these reactions involve the use of toxic (Stille) or highly basic (Kumada) reagents.In addition,the reagents required for transmetalation necessarily produce stoichiometric quantities of unwanted byproducts.We envisioned that the transmetalation step could be circumvented by decarboxylative metalation of carboxylic acid derivatives (Scheme 1),where the only byproduct would be CO_2.Since carboxylic acid derivatives are ubiquitous synthetic building blocks,the ability to access reactive organometallic species via decarboxylation offers clear practical advantages.