Alkali-metal-catalyzed addition of primary and secondary phosphines to carbodiimides. A general and efficient route to substituted phosphaguanidines.

Organo alkali metal compounds such as (n)BuLi and (Me3Si)2NK act as excellent catalyst precursors for the addition of phosphine P-H bonds to carbodiimides, offering a general and atom-economical route to substituted phosphaguanidines, with excellent tolerability to aromatic C-Br and C-Cl bonds.