Oxonia-Cope Prins Cyclizations: A Facile Method for the Synthesis of Tetrahydropyranones Bearing Quaternary Centers
作者:Jackline E. Dalgard、Scott D. Rychnovsky
DOI:10.1021/ja044736y
日期:2004.12.1
of a more nucleophilic silyl enol ether, such systems rearrange and cyclize to produce tetrahydropyranones. The substrates were prepared by silyl ketene acetal addition to ketenes. The rearrangement is compatible with tetrasubstituted silyl enol ethers, which result in the diastereoselective introduction of quaternary centers at the C3 position of the tetrahydropyran ring. The oxonia-Cope Prins rearrangement
已开发出一种新的阳离子级联反应,可以以良好的收率生产 4-四氢吡喃酮。该反应基于烯丙基取代的氧代碳鎓离子的简便的 2-oxonia Cope 重排。在更亲核的甲硅烷基烯醇醚存在下,此类系统重排和环化以产生四氢吡喃酮。通过将甲硅烷基乙烯酮缩醛加成到乙烯酮来制备基材。重排与四取代的甲硅烷基烯醇醚相容,导致在四氢吡喃环的 C3 位置非对映选择性地引入季中心。oxonia-Cope Prins 重排是获得四氢吡喃的通用新途径。