Base catalysed addition of acrolein to 1-ethyl-2,3,4,6,7,12-hexahydroindolo[2,3a] quinolizine (perch-lorate) 5b gives a pentacyclic alcohol 6b, which can be reduced in excellent yield to (±) homoeburnamine 7, a convenient precursor of (±) homoeburnamenine 9 and (±) homoeburnamonine 11.

中文翻译：

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长春花生物碱相关化合物的合成：（±）高纯胺的立体选择性合成

碱催化将丙烯醛加到1-乙基-2,3,4,6,7,12-六氢吲哚并[2,3a]奎宁嗪（高氯酸盐）5b中可得到五环醇6b，可将其优良的产率降低为（ ±）homoeburnamine 7，（±）homeburnamenine 9和（±）homoeburnamonine 11的便利前体。