Methoxyphenyl Substituted Bis(picolyl)phosphines and Phosphine Oxides

Three new derivatives of methoxyphenyl‐substituted bis(picolyl)phosphines 3 – 5 , the CH 2 TMS substituted bis(picolyl)phosphine ( 6 ) and related phosphine oxides 2b – 5b have been synthesized. Syntheses were accomplished by reacting the corresponding dichlorophosphines with picolylTMS ( 7 ). An improved synthesis of most of the starting materials is also presented and enables increased ligand yields in all cases. The new bis(picolyl)phosphines and phosphine oxides are extensively characterized by 1 H, 13 C and 31 P NMR spectroscopy and, in the case of the literature known tris(picolyl)phosphine ( 2 ) and its new phosphine oxide derivative, single‐crystal X‐ray analysis was applied to structure elucidation efforts. The determination of the molecular structure of ( o ‐methoxyphenyl)dichlorophosphine ( 3a ) was achieved by X‐ray analysis of a co‐crystal consisting of 3a and its rare phosphonic anhydride derivative 8 .