Diiodosilane. 4. Direct reduction of ketals and acetals in the presence of unprotected carbonyls. A case of inverted chemoselectivity

Article abstract of DOI:10.1055/s-1991-26533

Ketals and acetals are selectively reduced by diiodosilane to iodoalkanes in preference to ketones and aldehydes. This inversion of the normal order of reactivity of the 'protected' and 'unprotected' carbonyls allows partial reduction of polycarbonyl compounds with unusual regio- and chemoselectivity. Thus, 8,8-(ethylenedioxy)octan-2-one, 7,7-(ethylenedioxy)octanal, 3,3-(ethylenedioxy)-androstan-17-one and 3,3-(ethylenedioxy)pregnane-11,20-dione are converted to the corresponding iodo compounds.