Abstract The stability of phosphino (trimethylsilyl) carbenes bearing cyclic diamino substituents on phosphorus is strongly dependent on the steric hindrance of the nitrogen substituents. Phosphinocarbenes 3 and 7, derived from the trans-N, N′- diisopropylcyclohexane-1, 2-diamine and N, N′-diisopropyl-1, 2-ethanediamine, are not observed; instead the 1, 3-diphosphete 4 and a novel six-membered heterocycle 8, which ...
