Palladium(II) allylic complexes by carbene transmetalation and migratory insertion reactions: Synthesis and side reactions

New 1,1-alkoxy, aryl substituted palladium eta(3)-allyls [Pd(mu-Br){eta(3)-C(C(6)F(5))(OMe)CHR(1)CHR(2)}](2) can be synthesized from [W(CO)(5){C(OMe)CHR(1)=CHR(2)}] and a palladium perfluoroaryl complex. The allyls are formed by transmetalation of the carbene fragment followed by migratory insertion of C(6)F(5) to the putative and highly reactive Pd carbene complex. This reaction pathway predominates in all cases, but insertion of the double bond of the tungsten alkoxyvinylcarbenes into the Pd-C(6)F(5) bond leads to secondary products, namely C(6)F(5)(OMe)C=CR(1)CH(C(6)F(5))R(2). (C) 2009 Elsevier B.V. All rights reserved.