Thermal Rearrangement of [NP(OCH3)2]3 and [NP(OCH3)2]4

The thermal rearrangements of [NP(OCH3)2]3, [NP(OCD3)2]3, and [NP(OCH3)2]4 in the molten state or in o-dichlorobenzene to yield [RNP(O)OR]3 ot 4 have been studied. The rearrangement reaction is accelerated by the formation of the products. Moreover, evidence was obtained that the rearrangement is iniermolecular since the reaction rates are concentration dependent and “cross alkylation” products were detected from the interaction of [NP(OCH3)2]3 with [NP(OCD3)2]3. The rearrangement of the tetramer, [NP(OCH3)2]4, yields first a kinetically preferred geometric isomer of [CH3NP(O)OCH3]4 (VII) which is subsequently converted to the thermodynamically preferred isomer (VIII). The 1H, 31P, and 13C NMR spectra of the starting materials and products are discussed.