ADDITION OF NITRILE OXIDES TO GERMYL-SUBSTITUTED ETHYLENES

The reactions of [2 + 3] cycloaddition of nitrile oxides to mono- and 1,2-disubstituted germylalkenes proceed regioselectively and resulted 5-Ge-substituted isoxazolines-2 from triethylvinyl- and triethylallylg ermane and 4-Ge-isomers from beta-triorganylgermylstyrene and ethyl tr iorganylgermylacrylates. In the latter case the reaction occurs stereo specifically: Z-germylalkenes give cis-, while E-germylalkenes yield t rans-4,5-substituted isoxazolines. The structure of products obtained was determined by H-1-NMR spectroscopy and for 11a confirmed by single -crystal X-ray analysis. (C) 1998 Elsevier Science S.A. All rights res erved.