General Route to 2,4,5-Trisubstituted Piperidines from Enantiopure β-Amino Esters. Total Synthesis of Pseudodistomin B Triacetate and Pseudodistomin F
作者:Dawei Ma、Haiying Sun
DOI:10.1021/jo000447q
日期:2000.9.1
The Michael addition reaction of enantiopure beta-amino esters with methyl acrylate followed by Dieckmann condensation and enol silylation affords the enol ethers 6, which are hydrogenated with catalysis by Raney-Ni at 80 atm and 80 degrees C to provide 2,4, 5-trisubstituted piperidines with high diastereoselectivity. In this case Ni-H attacks the C-C double bond from the direction of the 2-alkyl group
对映纯β-氨基酯与丙烯酸甲酯的迈克尔加成反应,然后进行狄克曼缩合和烯醇甲硅烷基化,得到烯醇醚6,其通过阮内-镍在80atm和80℃下通过催化氢化而得到2,4,5-高非对映选择性的三取代哌啶。在这种情况下,Ni-H从2-烷基的方向攻击CC双键,以提供其中2,4,5-三取代的基团彼此都是顺式的产物。在没有N-Boc保护基的情况下氢化烯醇醚13得到产物15,其中4-羟基和5-酯部分反式为2-烷基。通过使用非对映选择性氢化产物9d和9e作为关键中间体,合成假乙酸二乙素B和乙酸假二素F。