A DIRECT SYNTHESIS OF 2-(TRIMETHYLSTANNYL)PYRROLES FROM MICHAEL ACCEPTORS AND STANNYLATED TOSYLMETHYL ISOCYANIDE

A series of 2-(trimethylstannyl)pyrroles 3, with substituents at the 3 - and 4-positions, is synthesized efficiently by a base-induced reacti on of stannylated TosMIC with Michael accepters. Stills cross-coupling s with bromobenzene and double cross-couplings with 1,4-dibromobenzene have been achieved successfully with the N-methyl derivative (5a) and the N-Boc derivative (6a) of 3-benzoyl-2-(trimethylstannyl)-4-phenylp yrrole (3a), despite the bulk of these stannylpyrroles. Homo coupling reactions of the same stannylpyrroles with the corresponding bromopyrr oles (prepared from stannylpyrroles 3 and NBS) were unsuccessful, prob ably for steric reasons.