Alkoxydienes via copper-promoted couplings: utilizing an alkyne effect.
Simple alkenes and alkynes, with 3-hexyne in particular, are found to be important pi ligands for oxidative copper-based coupling (modern Ullmann) reactions. This enabled syntheses of various alkoxydienes with removable protecting groups that are valuable substrates for Diels-Alder reactions from alcohols and vinyl boronate esters. In addition to demonstrating that 3-hexyne is a ligand for copper in both stoichiometric and catalytic reactions, the reaction atmosphere was found to play a critical role.
Winternheimer
David J
DJ
Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA.
Merlic
Craig A
CA