Efficient Biomimetic Synthesis of Indole Alkaloids of the Vallesiachotamine Group by a Domino Knoevenagel Hetero Diels-Alder Hydrogenation Sequence
作者:Lutz F. Tietze、Jürgen Bachmann、Jürgen Wichmann、Yifa Zhou、Thomas Raschke
DOI:10.1002/jlac.199719970515
日期:1997.5
An efficient three-step biomimetic synthesis of the four diastereomeric 18,19-dihydroantirhines 4a–d starting from the tetrahydrocarboline aldehydes 5a and 5b is described. Domino reaction of the aldehydes 5a and 5b, respectively, with Meldrum's acid (6) and the enol ethers 8a and 8b in the presence of catalytic amounts of ethylenediammonium diacetate leads to the strictosidine analogues 10a–d and
描述了从四烃基醛5a和5b开始的四个非对映体18,19-dihydroantirhines 4a-d的有效三步仿生合成。在催化量的乙二酸二铵二乙酸存在下,醛5a和5b分别与Meldrum酸(6)和烯醇醚8a和8b发生多米诺反应,分别在74中产生了严格的核苷类似物10a–d和11a–h。 –86%的产率,其中氢化作用主要产生15和16缬草胺胆碱吲哚生物碱的骨架(55-86%)。此外,还形成了少量的带有秋葵骨架的17和18(10–12%)。用LiAlH 4还原15和16可得到非对映体rac -18,19-dihydroantirhines 4a-d,产率为78-86%。