Murahashi coupling

Since the production of these other coupling reagents relies heavily upon organolithiums (especially in the case of organozinc and organomagnesium compounds), in bypassing these intermediates, this process is much more efficient.

The following year, Murahashi showed that coupling can occur between organolithium and alkenyl halides in the presence of tetrakis(triphenylphosphine)palladium catalyst.

At the start of the cycle, oxidative addition occurs between the Pd(0) catalyst (1) and an organo-halide to form an organo-Pd(II) complex (2).

In order to perform the reductive elimination that ultimately yields the final coupled product, a trans-cis-isomerization of (3) must occur to bring the ligands cis to each other, resulting in the cis-hetero-organometallic complex (4).

[6] While Pd(0)-catalyzed reactions are highly efficient for the cross-coupling of organo-halides and organolithium reagents, ruthenium catalysts have also been demonstrated.