Crystal Structure and Stereochemistry of (PS*, 2S*, 3aS*)-Hexahydro-2- (tert-Butylvinylthiophosphinyl)-6,6-Dimethylpyrrolo[1,2-b]isoxazole

The structure of the major product of the cycloaddition of 2,2-dimethyl-3,4-dihydro-2H-pyrrole N-oxide to tert-butyldivinylphosphine sulfide was analyzed by means of single-crystal X-ray diffraction technique. The analysis revealed two crystallographically independent molecules that differed in conformation of the fused five-membered heterocyclic rings. These rings were found to be two envelopes in one molecule and two half-chairs in the other. The studied compound was identified as an exo adduct of the expected erythro configuration and was found to favor a conformation in which the P = S and ring C-O bonds were anti and the C = C = P = S moiety was in the s-cis array. C14H26NOPS, space group P1BAR, a = 10.6004(7) angstrom, b = 12.3225(6) angstrom, c = 13.4404(7) angstrom, alpha = 104.073(4)-degrees, beta = 92.758(4)-degrees, gamma = 95.968(5)-degrees, V = 1688.802(4) angstrom3, Z = 4.