Rel-(1R,6S,7S,8R,9S)-9-Methyl-8-phenyl-6-[(1S,2R)-(2-phenylcyclohexyl)oxy]-4-aza-3,5-dioxatricyclo[5.2.1.04,9]decane

Abstract

The structure of the title compound, C26H31NO3, was determined by X-ray crystallography. It was found to be a unique bridged tricyclic nitroso acetal. Notable features include a chair conformation of the tetrahydro-1,2-oxazine ring and a highly pyramidalized N atom [sigma angles = 314.2 (6) degrees]. The configurations of the five contiguous stereogenic centers in the nitroso acetal establish that the tandem cycloaddition sequence proceeded via an exo-[4 + 2] endo-[3 + 2] pathway.