Shing Tony K M, Yeung Ying-Yeung
Department of Chemistry and Center of Novel Functional Molecules, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, China.
Chemistry. 2006 Nov 6;12(32):8367-77. doi: 10.1002/chem.200600669.
First total syntheses of unnatural (-)-14-epi-samaderine E (5) and natural (-)-samaderine Y (2) were accomplished from (S)-(+)-carvone (6) in 18 and 21 steps, respectively. The syntheses are short, efficient (with an average yield of 80 % plus for each transformation), enantiospecific, and produce nine new chiral centers. The crucial points of the syntheses included a regioselective allylic oxidation on ring C, regio- and stereoselective reduction of ketone, a stereocontrolled epoxidation, an epoxymethano-bridge formation, a chemoselective Grignard reaction, an intramolecular Diels-Alder reaction, an intramolecular aldol addition, and a newly developed manganese(III)-catalyzed allylic oxidation on ring A.
首次从不天然的（-）-14-表-萨马德林E（5）和天然的（-）-萨马德林Y（2）分别以（S）-（+）-香芹酮（6）为原料，经18步和21步反应完成了全合成。这些合成路线简短、高效（每个转化步骤的平均产率超过80%）、对映体特异性，并产生了九个新的手性中心。合成的关键步骤包括在C环上进行区域选择性烯丙基氧化、酮的区域和立体选择性还原、立体控制的环氧化、环氧甲桥的形成、化学选择性格氏反应、分子内狄尔斯-阿尔德反应、分子内羟醛加成以及新开发的在A环上的锰（III）催化烯丙基氧化。
