Fachbereich Chemie, Philipps-Universität Marburg , 35032 Marburg, Germany.
J Org Chem. 2013 Nov 1;78(21):10718-23. doi: 10.1021/jo4016979. Epub 2013 Oct 14.
(R)-Sarkomycin was prepared using a five-step total synthesis. Key steps in the enantioselective construction of the targeted scaffold were a rhodium-catalyzed asymmetric conjugate alkenyl addition with subsequent silyl trapping and a Mukaiyama aldol reaction with aqueous formaldehyde. Protection of the hydroxy group as a THP acetal and oxidative cleavage of the C,C-double bond provided a stable direct precursor to the natural product. The final liberation was carried out under slightly acidic conditions in a microwave-assisted reaction, resulting in a high yield of the "deceptive" sarkomycin. This represents the shortest enantioselective synthesis of this rather unstable compound to date and the first to employ asymmetric catalysis to introduce the stereogenic center.
（R）-Sarkomycin 采用五步全合成法制备。在目标支架的对映选择性构建中，关键步骤是铑催化的不对称共轭烯基加成，随后进行硅烷基捕获和与水合甲醛的 Mukaiyama 缩合反应。羟基保护为 THP 缩醛，C，C-双键氧化裂解提供了天然产物的稳定直接前体。最后在微波辅助反应中在微酸性条件下进行释放，得到“欺骗性” Sarkomycin 的高产率。这是迄今为止该不稳定化合物的最短对映选择性合成，也是首次采用不对称催化引入手性中心。
