Diastereoselective Synthesis of 2,3,6-Trisubstituted Tetrahydropyran-4-ones via Prins Cyclizations of Enecarbamates: A Formal Synthesis of (+)-Ratjadone A
作者:Kimberly N. Cossey、Raymond L. Funk
DOI:10.1021/ja046940r
日期:2004.10.1
precursors by alkylation of metalated (E)-enecarbamates with epoxides. The stereochemistry of the resultant trisubstituted (E)-enecarbamates is then transferred with high fidelity to afford the frequently observed and biologically significant all-cis-2,3,6-trisubstituted tetrahydropyran substructures of naturally occurring compounds. Other substituted tetrahydropyrans, including 2,3,5,6-tetrasubstituted
烯氨基甲酸酯被证明是 Prins 环化的极好终止基团。这种方法的一个值得注意的特点是通过金属化 (E)-烯氨基甲酸酯与环氧化物的烷基化,可以轻松、立体选择性地构建环化前体。然后以高保真度转移所得三取代 (E)-烯氨基甲酸酯的立体化学,以提供经常观察到且具有生物学意义的天然化合物的全顺-2,3,6-三取代四氢吡喃亚结构。其他取代的四氢吡喃,包括 2,3,5,6-四取代、顺-2,3-二取代和顺-2,6-二取代,也可使用。这种方法促进了核输出抑制剂 (+)-ratjadone A 的异常简洁的正式全合成。