Addition of nitrile oxides to 2,3-dihydrofurylsilanes. Crystal and molecular structure of tetrahydrofuro-[2,3-d]-isoxazolylsilanes

Silylsubstituted tetrahydrofuro-[2,3-d]-isoxazoles were prepared by the [2 + 3] cycloaddition of nitrile oxides to 5-(2,3-dihydrofuryl)silanes. Compou nds with two condensed bicycles at the silicon atom: bis[6a-(3-methyl-3a,4, 5,6a-tetrahydrofuro-[2,3 -d]-isoxazolyl)]dimethylsilanes and bis[6a-(3-meth yl-3a,4,5,6a-tetrahydrofuro-[2,3-d]-isoxazolyl)]diphenylsilanes were prepar ed by the addition of acetonitrile oxide to the corresponding bis[5-(2,3-di hydrofuryl)]silanes. X-ray analysis demonstrated that 3-methyl-6a-trimethyl silyl-3a,4, 5,6a-tetrahydrofuro-[2,3-d]-isoxazole exists as RR/SS enantiome rs, while bis[6a-(3-methyl-3a,4,5,6a-tetrahydrofuro-[2,3-d]-isoxazolyl)]dip henylsilane- SSRR/RRSS enantiomers. (C) 1999 Elsevier Science S.A. All righ ts reserved.