We have developed a route for the stereoselective synthesis of 1-oxa-2,2-(dimesityl)silacyclopentane acetals, intermediates in the synthesis of highly functionalized 1,3-diols. This route involves a diastereoselective conjugate addition reaction of a hydrosilyl anion, a subsequent diastereoselective enolate alkylation, and a fluoride-catalyzed intramolecular hydrosilylation reaction to afford the oxasilacyclopentane acetal. A highly selective nucleophilic substitution reaction, followed by oxidation of the C-Si bond, leads to the desired polyol.

Diastereoselective syntheses Diastereoselective syntheses O 0031Utilization of 1-Oxa-2,2-(dimethyl)silacyclopentane Acetals in the Stereoselective Synthesis of Polyols. -Oxasilacyclopentanes are prepared by diastereoselective conjugate addition reaction of silyllithium compound (II), subsequent diastereoselective enolate alkylation, and fluoride-catalyzed hydrosilyation. The products are precursors for highly functionalized 1,3-diols, which are formed by selective nucleophilic substitution reaction of the oxasilacyclopentanes, followed by oxidation of the C-Si bond. The synthesis of oxasilacyclopentane (XXII) demonstrates that the route can be performed in one pot with high efficiency. -(POWELL, S. A.; TENENBAUM, J. M.; WOERPEL*, K. A.; J.