Total Synthesis of (<i>R</i>)-Sarkomycin via Asymmetric Rhodium-Catalyzed Conjugate Addition
作者:Johannes Westmeier、Steffen Kress、Christopher Pfaff、Paultheo von Zezschwitz
DOI:10.1021/jo4016979
日期:2013.11.1
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
(R)-Sarkomycin使用五步全合成法制备。靶向支架的对映选择性构建的关键步骤是铑催化的不对称共轭链烯基加成反应,随后进行甲硅烷基捕集以及与甲醛水溶液的Mukaiyama醛醇缩合反应。作为THP缩醛的羟基保护和C,C-双键的氧化裂解为天然产物提供了稳定的直接前体。最终的释放是在微酸性条件下在微波辅助反应中进行的,从而导致了“欺骗性”的萨克霉素的高收率。这代表了迄今为止该最不稳定化合物的最短对映选择性合成,并且是第一个采用不对称催化引入立体异构中心的化合物。