A Novel Mild Deprotection Method for Phosphine–Boranes

Abstract Treatment of phosphine–boranes with molecular sieves 4Å in a mixture of an ethereal solvent and an alcohol provided deprotected free phosphines in quantitative yields. The phosphines can be obtained by a simple filtration/crystallization procedure in most cases. It should be noted that the current method is successfully applied to the deprotection of a phosphite–borane for the first time.