Total Synthesis of Ustiloxin D and Considerations on the Origin of Selectivity of the Asymmetric Allylic Alkylation
作者:Andrew M. Sawayama、Hiroko Tanaka、Thomas J. Wandless
DOI:10.1021/jo048854f
日期:2004.12.1
C9. The chiral aryl−alkyl ether was assembled using a Pd-catalyzed asymmetric allylic alkylation that notably delivered a product with stereochemistry opposite to that predicted by precedent. The linear tetrapeptide was subsequently cyclized to produce ustiloxin D. The mechanistic origin of the allylic alkylation selectivity was further investigated, and a working hypothesis for the origin of the observed
作为细胞周期检查点抑制剂研究的一部分,抗有丝分裂天然产物ustiloxin D的不对称合成已经完成。Salen-Al催化的醛醇缩合反应用于构建手性恶唑啉9(99%收率,98%ee),具有安装必要的1,2-氨基醇官能团以及为C9处所需的甲基氨基提供有效合成子的双重目的。手性芳基-烷基醚是使用Pd催化的不对称烯丙基烷基化反应组装而成的,该反应显着地提供了立体化学与先例所预测的相反的产物。随后将线性四肽环化以产生ustiloxinD。进一步研究了烯丙基烷基化选择性的机理起源,并提出了观察到的立体选择性起源的可行假设。