Mechanochemical one-pot Barbier/Simmons-Smith reaction via sequential zinc activation.

We report a mechanochemical one-pot Barbier/Simmons-Smith reaction enabled by ball-milling-mediated activation of zinc(0). This operationally simple method generates organozinc intermediates in situ and uses them sequentially in allylation and cyclopropanation without intermediate work-up. The protocol tolerates a broad range of ketones, exhibits selectivity over other carbonyl groups, and is compatible with various physical forms of zinc metal. In selected cases, the reaction proceeds with markedly enhanced diastereoselectivity under minimal-solvent milling conditions and was demonstrated on a gram scale using standard ball-milling equipment. Comparative studies show advantages over conventional solution and neat conditions, highlighting how mechanochemistry can uniquely enable tandem organometallic processes as for C-C bond construction.