An Unusual Doubly Substituted Product from the Phase-Transfer-Catalyzed Heck Reactions of o-Bromobenzaldehydes with Methyl Acrylate

Article abstract of DOI:10.1021/jo00034a041

The reactions of o-bromobenzaldehydes with methyl acrylate under Heck conditions and with phase-transfer catalysis to yield significant amounts of doubly substituted deformylatet products 1A-E in addition to the expected o-formyl cinnamates 2A-E are reported.X-ray crystallography of one such product (4) established that the bromine was replaced by a propionate and the formyl group by an acrylate residue.Employment of deuterium-labeled substrates showed that the hydrogen atom of the formyl group of the substrate was transferred intramolecularly and regiospecifically to the benzylic carbon of the propionate substituent of the product.A tentative hypothesis is advanced to explain these and other experimental findings.