Stereocontrolled reactions induced by a thermolabile group. Synthesis of optically active 1,3-diols

Article abstract of DOI:10.1016/S0040-4020(01)89007-4

Wittig Horner-Michael reactions of phosphonates with optically active lactol 1 lead preferentially to one diastereoisomer. 2. Force field calculations conducted on one pair of diastereoisomers 2c and 2′c predict that these isomers must exist in different conformations of similar energies. ¹H NMR data are in good agreement with these predictions. The dihydrofurans obtained by retro Diels-Alder reactions of 2 are easily transformed into optically pure 1,3-diols, precursors of R-(+)-α-lipoic acid and (-)-(1R,3R,5s)-1,3-dimethyl-2,9-dioxabicylco [3.3.1]nonane.