Department of Chemistry and Biochemistry, National Chung Cheng University, Minhsiung, Taiwan 621.
J Org Chem. 2012 Jul 20;77(14):6139-46. doi: 10.1021/jo300923e. Epub 2012 Jul 3.
The first enantioselective syntheses of cladoacetals A (1a, overall yield: 16%) and B (1b, overall yield: 34%) from crotonaldehyde in nine and seven steps, respectively, have been accomplished. Sharpless asymmetric dihydroxylation, Suzuki coupling, and acid-catalyzed intramolecular acetalization were the key steps in the syntheses. The absolute configuration of natural (+)-cladoacetal A was affirmed to be 1S,3S,4R, whereas that of (-)-cladoacetal B was affirmed to be 1R,3S,4S.
首次以巴豆醛为起始原料，经 9 步和 7 步反应分别以 16%和 34%的总收率完成了克拉多酯 A（1a）和克拉多酯 B（1b）的对映选择性全合成。关键步骤包括 Sharpless 不对称双羟化反应、Suzuki 偶联反应和酸催化的分子内环缩醛化反应。天然（+）-克拉多酯 A 的绝对构型被确认为 1S,3S,4R，而（-）-克拉多酯 B 的绝对构型被确认为 1R,3S,4S。
