Synthesis and stereochemistry of substituted 1,3-dioxa-2-silacyclohexanes:VII. Synthesis and stereochemistry of substituted 2-vinyl-2-methyl-1,3-dioxa-2-silacyclohexanes

The stereochemistry of substituted 2-vinyl-2-methyl-1,3-dioxa-2-silacyclohe xanes was studied by H-1 and C-13 NMR spectroscopy. The configurational and conformational assignment of it mixture of 2-vinyl-2,4-dimethyl-1,3-dioxa- 2-silacyclohexane diastereorners with various ratios of tile cis and trans forms was made. The molecules of both conformers occur chiefly in tile chai r conformartion with equatorial location of the methyl group at the C-4 ato m. The experimental data were confirmed by AM1 and MM+ optimization of the molecular geometry.