(2aS,3S,6S,7S,7bR)-7-[(Dimethylphenyl)silyl]-2-oxo-6-[(1R,2S)-2-phenylcyclohexyloxy]-2a,3,6,7,7a,7b-hexahydro-2H-1,4,5-trioxa-4a-azacyclopenta[cd]indene-3-carboxylic Acid 1-Methylethyl Ester

The structure of the title compound C₃₁H₃₉NO₇Si was determined and found to be a fused tricyclic nitroso acetal. Remarkable features include a twist boat conformation of the tetrahydro-1,2-oxazine ring and a highly pyramidalized N atom [[Sigma](angles) = 310.6(6°]. Three of the contiguous stereocenters in the nitroso acetal are of the same correct relative and absolute configuration as found in (+)-crotanecine.

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