INTRA-MOLECULAR PHOTO-CHEMICAL CYCLO-ADDITION OF A VINYLOGOUS IMIDE - CRYSTAL AND MOLECULAR-STRUCTURE OF A TETRACYCLIC C17H25O2N PRODUCT

Pyrex-filtered irradiation of N-acetyl-3-(N-cyclohexenylmethyl)amino-5, 5-dimethyl-2-cyclohexen-l-one (1) provides an acyl migration product and an intramolecular cycloaddition product. The cycloaddition reaction was shown to be thermally reversible. The structure of the tetracyclic product was inferred from chemical and spectroscopic data, and the stereochemistry was fully defined via X-ray crystal-structure analysis. Crystal data (from single- crystal diffractometry, Mo Kα, = 0.70926 Å, at T = 20 ± 1 °C): a = 20.815 (8), b = 10.875 (2), c = 6.625 (1) Å; 2 2 2, Z = 4; dc = 1.218 and da = 1.19 g cm-3 by flotation in NaBr solutions; F(000) = 600. © 1979, American Chemical Society. All rights reserved.