MODIFIED BOROHYDRIDE AGENTS, BIS (TRIPHENYLPHOSPHINE) (TETRA-HYDROBORATO)ZINC COMPLEX [Zn(BH4 2(PPh3)2] AND (TRIPHENYLPHOSPHINE) (TETRAHYDROBORATO)ZINC COMPLEX [Zn(BH4)2(PPh3)]. NEW LIGAND METAL BOROHYDRIDES AS STABLE, EFFICIENT, AND VERSATILE REDUCING AGENTS

Bis(triphenylphosphine)(tetrahydroborato)zinc and (triphenylphosphine)(tetrahydroborato) zinc complexes have been used for the efficient reductions of varieties of organic compounds in THF or under solvent free conditions. Selective reduction of aldehydes, ketones, α,β-unsaturated carbonyl compounds, and acyl chlorides to their corresponding alcohols and aryl, alkyl, aroyl, and sulfonyl azides to their corresponding mines and amides are described. Bis(triphenylphosphine)(tetrahydroboratro)zinc complex shows promising shelf stability and is much more stable than its mono triphenylphosphine analogue. The reducing ability of the two complexes is more or less the same.