Molecular structure of 2-tert-butyl-2-oxo-1,3,2-dioxaphosphepine and its benzo derivative

X-ray structure investigation of the title compounds displays a chair form with equatorial alkyl substituent. 1H NMR and PM3 semiempirical calculations have been also applied and the effect of the planar fragment on the chair–twist-boat equilibrium has been observed. q 2004 Elsevier B.V. All rights reserved