Addition reactions of aldehydes to lithium enolates of 1,3-dioxolan-4-ones: A configurational reassessment

The results for the addition reactions of chiral lithium (2S)-enolates of 1 ,3-dioxolan-4-ones to aldehydes and to acetophenone, yielding the correspon ding dioxolanone alcohols have been revised. The results reported herein di ffer from those reported in the literature, both in product distribution an d in the stereochemical assignment of the products. In fact, in several cas es no stereocontrol was observed at the C5 carbon atom of the lithium enola te. The (2S,5R,1'S)/(2S,5R,1'R) stereochemistry was also reassessed for sev eral dioxolanone alcohols. The major conformers are considered to have an i ntramolecular hydrogen-bonded five-membered ring structure instead of the s ix-membered ring structure previously suggested for cyclic dioxolanone alco hols.