Highly selective palladium-benzothiazole carbene-catalyzed allylation of active methylene compounds under neutral conditions

The Pd-benzothiazol-2-ylidene complex I was found to be a chemoselective catalyst for the Tsuji-Trost allylation of active methylene compounds carried out under neutral conditions and using carbonates as allylating agents. The proposed protocol consists in a simplified procedure adopting an in situ prepared catalyst from Pd(2)dba(3) and 3-methylbenzothiazolium salt V as precursors. A comparison of the performance of benzothiazole carbene with phosphanes and an analogous imidazolium carbene ligand is also proposed.