M. Soleilhavoup et al., NUCLEOPHILIC ADDITIONS TO A DIPHOSPHIRENIUM SALT - RING-OPENING AND RING EXPANSION REACTIONS, Journal of the Chemical Society, Chemical Communications, (3), 1994, pp. 337-338
P-Bis(diisopropylamino)-C-diisopropylamino diphosphirenium tetrafluoro
borate 1 reacts with lithium diisopropylamide and tert-butyl isocyanid
e affording phosphaalkene 3 and the original four-membered heterocycle
5;5 is characterized by X-ray diffraction and its chemical reactivity
.