Since the discovery of Brook rearrangement in 19581, acylsilanes have been recognized as starting materials for silyl enol ethers 2 and useful synthetic intermediates 3. Acylsilanes are functionally quite unique, possessing various reactivities and selectivity 4. We also developed a method for 1,2asymmetric induction in acyclic system utilizing ~x-chiral acylsilanes as c~-chiral aldehyde-equivalents to afford products with high diastereofacial selectivity5.
The synthesis of acylsilanes via 1,3-dithianes was developed by Brook 6 and Corey 7, and extensive studies on the synthetic methods for acylsilanes were recently reported 4. However, the reported methods are narrow in scope and have some limitations. For instances, the problem of ]3elimination at the lithiation of dithianes derived from ~-alkoxy aldehydes is unsolved yet, and partial racemization of ~-chiml aldehydes takes place at a converting step. Acid chlorides 8 were found to give some acylsilanes by treatment with tris(trimethylsilyl)aluminum (AI(SiMe3)3)9, but acid chlorides generally require rather drastic conditions.