Synthesis and x-ray crystal structure of an optically pure tripodal C3-symmetric tritertiary phosphine bearing chirality on phosphorus

The prepn. of the optically pure tritertiary phosphine (RRR)-I is reported. The route followed involves deprotonation of optically pure (R)-P(BH3)Me(CMe3)Ph, the reaction of the resulting carbanion with MeSiCl3, followed by removal with morpholine of the BH3-protecting groups from the tritertiary phosphine-borane (RRR)-MeSi[CH2P(BH3)(CMe3)Ph]3. The x-ray crystal structure of I and its norbornadienerhodium complex are reported. Furthermore, sepn. of the racemic phosphine-borane can be conveniently carried out by using medium-pressure liq. chromatog. with cellulose triacetate as a chiral stationary phase. [on SciFinder(R)]