Coupling constants 1J(15N,31P) as a probe for the conformational equilibria of 2-amino-substituted 1,3,2λ5-oxazaphosphinan-2-ones†

Abstract

The ¹⁵N NMR spectra of both P(2) diastereomers of the trans-fused 2-bis(2-chloroethyl)amino-3,4,4a,5,6,7,8,8a-octahydro-1,3,2λ⁵-benzoxazaphosphinin-2-ones and their 3-methyl and 3-benzyl derivatives have been measured. Depending on the P(2) configuration, the coupling constants ¹J(¹⁵N,³¹P) vary markedly. The applicability of the coupling between exocyclic nitrogen and phosphorus for determination of the heteroring conformation is discussed.