Free-radical chemistry and photochemistry of organophosphorus intermediates. VII. Intermediacy and configuration of phosphoranyl radicals in the reaction of labeled tert-butoxy radical with tri-tert-butyl phosphite

Free-radical chemistry of organophosphorus derivatives. Nonequivalence of alkoxy groups in (RO)4P

“…Reaction of p-methylbenzyloxy radical with benzyl diethyl phosphite (10) at 65°( eq 2) gave the same prodp-CH3C6H4CH20• + CeH5CH2OP(OEt)2-10 5(41.5%)+6(49.3%) (2) ß scission R'O• + P(OR)3-> R'OP(OR)3-->-1 R'+OP(OR)3 (1) Esr hyperfine splittings for certain other phosphoranyl radicals, F4P•,3 C14P•,4 and (CH3)3POC4H9-i,5 have been interpreted in terms of a geometry which approaches trigonal bipyramidal with the odd electron in an equatorial position. Unfortunately, for 1 the absence of hyperfine splittings precludes such an assessment of configuration.…”

Kinetics and Mechanism of the Reaction of Peroxy-compounds with Phosphites, Sulphides, and Aromatic Amines

“…11 In principle, the formation of a radical with an unpaired electron at the phosphorus atom as a kinetically independent species is possible also in the reactions of trialkyl phosphites with free radicals, in particular with t=BuO radicals. Recently this was confirmed experimentally by the observation of the chemically induced polarisation of 31 P nuclei in trialkyl phosphates and dialkyl phosphonates 68 , by the observation of the ESR spectra of t-butyl radicals 69 as the decomposition products of the primary phosphoranyl radicals (RO) 3 P-O-t-Bu, and also by the analysis of the distribution of the 14 C isotope label in tri-t-butyl phosphate 70 .…”

31P CIDNP in the reactions of phosphoranyl radicals

“…The question has been under discussion for a long time as to whether the phosphoranyl structure t-C4HgOP(OR),, certainly formed in this case, is only a transient state or a discrete free radical intermediate. 2 The investigation of the polarisation of phosphorus nuclei as well as the elucidation of some other features of the reactions mentioned provide an unambiguous answer to this question., the thermal decomposition of di-t-butyl peroxide in tributyl phosphite at 180°C. Other trialkyl phosphites reveal similar slP CIDNP patterns.…”