[Rh(Cp)]-catalyzed arylfluorination of α-diazoketoesters for facile synthesis of α-aryl-α-fluoroketoesters

Here we describe the Cp*Rh( iii )-catalyzed cascade arylfluorination reactions of α-diazoketoesters with arylboronic acids and N -fluorobenzenesulfonimide for one-pot C(sp 3 )-C(aryl) and C(sp 3 )-F bond formation. The arylfluorination reaction can be accomplished with remarkable chemo- and regioselectivity. Our mechanistic investigation showed that the Rh-catalyzed arylfluorination of diazoacetates occurred by (1) transmetalation of arylboronic acids to form an arylrhodium( iii ) complex, (2) coupling of diazomalonates with the arylrhodium( iii ) complex to form carbene-rhodium, (3) migratory carbene insertion to form a diketonato-rhodium( iii ) complex - probably via rearrangement of the putative σ-alkylrhodium( iii ) complex, and (4) electrophilic fluorination of the diketonato-rhodium to form the α-aryl-α-fluoromalonates. The Cp*Rh( iii )-catalyzed cascade arylfluorination reactions of α-diazoketoesters with arylboronic acids and N -fluorobenzenesulfonimide for one-pot C(sp 3 )-C(aryl) and C(sp 3 )-F bond formation was achieved.