Synthesis of hydroxy pyrrolidines and piperidines via free-radical cyclisations
Synthesis of hydroxy pyrrolidines and piperidines via free-radical cyclisations
复制标题
通过自由基环化合成羟基吡咯烷和哌啶
DOI：
10.1039/a707740h
复制
发表时间：
1998
期刊：
影响因子：
--
通讯作者：
R. M. Pettifer
中科院分区：
文献类型：
--
作者：
A. Parsons;R. M. Pettifer
研究了在温和的中性反应条件下，氢化锡催化多种α和β氨基醛的环化反应，生成取代的吡咯烷和哌啶。从相应的氨基酯或醇制备的氨基醛前体被提纯或立即在沸腾的苯中与Bu3SnH-AIBN反应。该方法是通用的，中间体O-锡基酮的环化反应是利用各种(贫电子或富电子)受体碳-碳双键，在工作后得到羟基-吡咯烷或-哌啶类化合物。使用炔烃或α，β-不饱和酰胺自由基受体的相关环化反应被证明是有问题的和低产率的。由α，β不饱和酮与氢化锡反应生成的烯丙基O-锡基酮的自由基环化反应也被证明在吡咯烷/哌啶的合成中有应用。一项稀释研究表明，肉桂基双键上的环化是不可逆的。
The tin hydride-mediated cyclisation of a variety of α- and β-amino aldehydes to form substituted pyrrolidines and piperidines under mild, neutral reaction conditions has been investigated. The amino aldehyde precursors, prepared from the corresponding amino ester or alcohol, are purified or immediately reacted with Bu3SnH–AIBN in boiling benzene. The method is shown to be general and cyclisation of the intermediate O-stannyl ketyl is observed using a variety of (electron poor or rich) acceptor carbon–carbon double bonds to afford hydroxy-pyrrolidines or -piperidines after work-up. Related cyclisations using an alkyne or α,β-unsaturated amide radical acceptor are shown to be problematic and low-yielding. Radical cyclisation of allylic O-stannyl ketyls, generated from reaction of α,β-unsaturated ketones with tin hydride, are also shown to have application in pyrrolidine/piperidine synthesis. A dilution study suggests that the cyclisation onto a cinnamyl double bond is irreversible.