Preparation of Aldehydes from Acid Chlorides Using Copper Tetrahydroborate Complexes

Article abstract of DOI:10.1021/jo01305a015

It has been proposed previously that covalent, transition-metal tetrahydroborate complexes constitute a new class of stoichiometric reducing agents for organic synthesis.Thus, tetrahydroborate complexes of copper having phosphine and phosphite ligands are prepared from sodium borohydride, cuprous chloride, and the appropriate ligand in chloroform-ethanol solution.It is demonstrated that these compounds reduce acid chlorides to aldehydes in acetone containing excess triphenylphosphine under mild conditions and in high yields.The reactivity for the complexes L2CuBH4increases in the series Ph3P < (i-C3H7O)3P < (CH3O)3P, parallel to the increasing electron-donor ability of the ligands L.