| Abstract: | Variously substituted 4,5-dihydro-5-vinylisoxazoles, obtained by regio- and stereospecific cycloaddition of nitrile oxides to dienes, undergo smooth OsO4-catalyzed cis-hydroxylation to give amino-polyol precursors. The reaction is ‘anti’-selective, the diastereoisomeric ratios ranging from 73:27 up to ≥ 99:1. Thus, the cycloaddition/osmylation sequence allows the control of the relative configuration of up to four contiguous asymmetric centers. A sulfoxide-mediated approach to enantiomerically pure compounds is also described. |
