Endocyclic P-P bond cleavage in carbaborane-substituted 1,2-diphosphetane: a new route to secondary phosphinocarbaboranes

Carbaborane-substituted 1,2-diphosphetane reacts with elemental lithium and hydrogen chloride to give exclusively secondary mono- and bis(phosphino)carbaboranes. The latter reacts with two equivalents of formaldehyde and one equivalent of aniline to give a carbaborane-substituted 1-aza-3,6-diphosphepane.