@article{Exner:171732, title = {Total Asymmetric Syntheses of beta-Hydroxy-delta-lactones via Umpolung with Sulfur Dioxide}, author = {Exner, Claudia J. and Laclef, Sylvain and Poli, Florent and Turks, Maris and Vogel, Pierre}, journal = {Journal Of Organic Chemistry}, volume = {76}, pages = {840-845}, year = {2011}, abstract = {Cyclic stereotriads and stereotetrads of the beta-hydroxy-delta-lactone type, e.g. prelactones B and E, common in polyketides and polypropionates, are prepared via SO2-induced oxyallylations of enoxysilanes with (1E,3Z)-1-(1-phenylethoxy)penta-1,3-dien-3-yl carboxylates. Using (Z)- or (E)-enoxysilanes both 4,5-cis- or 4,5-trans-delta-lactones are obtained. Depending on the reduction method applied to the obtained aldol intermediates 5,6-trans or 5,6-cis-derivatives are formed. The delta-lactones can be prepared in both their enantiomeric forms depending on the (1R)- or (1S)-configuration of the starting 1-(1-phenylethoxy)penta-1,3-dienes.}, url = {http://infoscience.epfl.ch/record/171732}, doi = {10.1021/jo102035d}, }