Synthetic applications of the photochemically induced addition of oxycarbinyl species to α-enones. Part II. The addition of ketals, aldehydes, and polyfunctional species

Alcohols possessing an α-hydrogen, acetals, and aldehydes undergo photochemically induced conjugate addition to a variety of α-enones to give 1,4-ketols, 1,4-keto ketols and 1,4-diketones respectively. It appears that the aldehydes frequently succeed where acetals and alcohols fail, and acetals where alcohols fail. It is therefore possible to employ polyfunctional addenda and achieve addition at only one of the activated sites. The reactions are always regiospecific and are frequently completely stereoselective.