Alkene Adducts of Cyclic Thiazenes - Identification of Exo and Endo Addition of 1,3,2,4,6-Dithiatriazines to 1,5-Norbornadiene by 2-D Nmr Methods and the Crystal-Structure of a Single-Molecule in Which Both Modes of Addition Are Displayed

by Boere, R. T.; Eng, J. A.; Preuss, K.; Parvez, M.; Bryan, C. D.; Cordes, A. W.

4-CF3-C6H4-CN3S2, 1, forms symmetrical sulfur-bound adducts with norbornene (NBE), norbornadiene (NBD), and 1-heptene (C7H14), which were studied by H-1, C-13, COSY-45, and HETCORR NMR. 1NBE exists in solution in a single isomeric form which corresponds to that found in the solid state for 4-CH3O-C6H4-CN3S2.NBE by single-crystal X-ray diffraction: orthorhombic, P2(1)2(1)2(1) with Z = 4, a = 10.224(3), b = 10.369(5), c = 14.075(5). R = 0.0475 and R(w) = 0.0492 for 634 data. 1 NBD exists in solution in two isomeric forms which are not interchangeable. One of these corresponds to that found in the NBE adduct, i.e. exo addition; the other is the first example of endo addition. Two bis adducts of stoichiometry NBD.21 have been prepared and separated. They are isomers exhibiting eno-exo and exo-endo addition. The structure of the latter was confirmed by X-ray diffraction: orthorhombic, Pcab with Z = 8, a = 7.816(2), b = 17.264(3), c = 36.842(5). R = 0.068 and R(w) = 0.106 for 1506 data. 1.C7H14 exists as a mixture of syn and anti isomers. NMR structure parameters derived here have been applied to published data on over 15 thiazene NBE and NBD adducts.

Canadian Journal of Chemistry-Revue Canadienne de Chimie
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