Concise Total Synthesis of (±)-Cephalotaxine via a Transannulation Strategy: Development of a Facile Reductive oxy-Nazarov Cyclization
作者:Wei-Dong Z. Li、Wei-Guo Duo、Cheng-Han Zhuang
DOI:10.1021/ol201390r
日期:2011.7.1
A concise total synthesis of (±)-cephalotaxine (1) has been achieved from dioxolanone derivative 15 via a transannulation strategy. The key transformation is a facile reductive oxy-Nazarov cyclization as illustrated above, involving presumably a tethered 1,2-oxidopentadienyl cation species 7a or 7b, which represents a new variant of the oxy-Nazarov cyclization and constitutes an effective, regio- and
从二氧戊环酮衍生物15通过转环策略已实现了(±)-头孢他辛(1)的简明全合成。关键的转化是如上所述的简便的还原性氧-纳扎罗夫环化反应,大概涉及束缚的1,2-氧化戊二烯基阳离子种类7a或7b,它代表了氧-纳扎罗夫环化反应的新变体,并构成了有效的,区域特异性和立体特异性在轻度氢化物还原条件下的5-羟基环戊烯酮环化方案。