P(OC6H3But2-2,4)2N(Me)CON(Me)PPh2: the facile route to an unsymmetrically substituted bisphosphinourea

The phosphinourea derivative PPh2N(Me)CON(Me)H 1a and the phosphoramidite derivative P(OC6H3But2-2,4)2N(Me)CON(Me)H 1b and their conversion to the unsymmetrically substituted urea phosphinophosphoramidite P(OC6H3But2-2,4)2N(Me)CON(Me)PPh22b are described. These ligands were reacted with [Mo(CO)4(NCMe)2] to the cis complexes cis-[Mo(CO)4{P(OC6H3But2-2,4)2N(Me)CON(Me)H}2]3b and cis-[Mo(CO)4{P (OC6H3But2-2,4)2N(Me)CON(Me)PPh2}2]4b, respectively. The structure of 3b and 4b was determined by multinuclear NMR spectroscopy.