2,4-diphosphoranediyl-l,3-diphosphetanes

Article abstract of DOI:10.1002/cber.19971301027

The 1,3-dichloro- and 1,3-dibromo-substituted title compounds 5b, c result from the condensation of triphenylphosphonium-bis(trimethylsilyl)methylide 1 with PC13 and PBr3. The chloro derivative 5b undergoes a variety of single and double substitution reactions, of which some have merely been tested and others have been made preparative use of. The substitution of one chloride by an ylidyl, amino, phosphino, or metal carbonyl group is accompanied by the spontaneous dissociation of the other P-C1 bond to yield the 1,3-diphosphetenium chlorides 14/15, 19, 31 and 36, respectively. In other cases (9, 27, 32) dissociation can be achieved by means of a Lewis acid. Protonation of 5b occurs at the carbon ring members; methylation and formation of transition metal complexes occurs at a phosphorus ring member. PC13 degrades the four-membered ring of 5b or enlarges the ring to yield 3,5-diphosphoranediyl-l,2,4-triphospholane derivatives 39, 40, 42. Keywords: Phosphorus / Heterocycles / Phosphorus ylides / Phosphoranediyl and phosphonio substituants / P-C1 bond dissociation WILEY-VCH Verlag GmbH.