Phosphanalkylene, 54 [1a] . Kumulierte ylide, 21 [1b] . Ein neuer weg zu N ‐substituierten (triphenylphosphoranyliden)keteniminen

Phosphane Alkylenes, 54 [1a] . – Cumulated Ylides, 21 [1b] . – A New Way to N ‐Substituted (Triphenylphosphoranylidene)‐ketenimines Reaction of methylenetriphenylphosphorane ( 1 ) with isothiocyanates 5 leads to ylides 6B , which can be methylated at the S atom to give the phosphonium salts 8 . Treatment of 8 with sodium methanolate gives rise to formation of the phosphoranes 10 , which on treatment with sodium bis(trimethylsilyl)‐amide undergo β‐elimination to form the N ‐substituted (tri‐phenylphosphoranylidene)ketenimines 3 .