The photoinduced reactions of aromatic carbonyl compounds and diaryldiazomethanes with phosphorus derivatives were investigated by EPR and laser flash photolysis techniques. Triplet ketones reacted with tetraethyl pyrophosphite via a mechanism akin to a homolytic dieplacement ( SH~p)ro cess at an almost diffusion controlled rate (km = (7.96 * 0.04) X l@ M-' for benzophenone). Triplet benzophenone reacted very rapidly with tetraphenyldiphosphine (km = 2 x lo8 M-' s-' ), Tetraethyl pyrophosphite also underwent homolytic attack by triplet diphenylcarbene (km = (7.4 * 0.7) X los M-' s-') to give a diradical intermediate (or transition state) which, by @-fragmentationg, ave Ph&OP(O)(OEt),. Product studies supported the proposed mechanism. In contrast with diphenylcarbene, fluorenylidene appeared to react via a nonradical mechanism.
Reactions of carbenes and photoexcited ketones with phosphorus compounds
Alberti A;
1986
Abstract
The photoinduced reactions of aromatic carbonyl compounds and diaryldiazomethanes with phosphorus derivatives were investigated by EPR and laser flash photolysis techniques. Triplet ketones reacted with tetraethyl pyrophosphite via a mechanism akin to a homolytic dieplacement ( SH~p)ro cess at an almost diffusion controlled rate (km = (7.96 * 0.04) X l@ M-' for benzophenone). Triplet benzophenone reacted very rapidly with tetraphenyldiphosphine (km = 2 x lo8 M-' s-' ), Tetraethyl pyrophosphite also underwent homolytic attack by triplet diphenylcarbene (km = (7.4 * 0.7) X los M-' s-') to give a diradical intermediate (or transition state) which, by @-fragmentationg, ave Ph&OP(O)(OEt),. Product studies supported the proposed mechanism. In contrast with diphenylcarbene, fluorenylidene appeared to react via a nonradical mechanism.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
