Vinylogous Mukaiyama aldol reactions with 4-oxy-2-trimethylsilyloxypyrroles: relevance to castanospermine synthesis
Vinylogous Mukaiyama aldol reactions with 4-oxy-2-trimethylsilyloxypyrroles: relevance to castanospermine synthesis
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DOI：
10.1186/1860-5397-3-38
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发表时间：
2007-11-03
影响因子：
2.7
通讯作者：
Su, Hong
中科院分区：
文献类型：
--
作者：
Hunter, Roger;Rees-Jones, Sophie C. M.;Su, Hong
背景资料：研究了一系列N-取代的4-氧-2-三甲基硅氧基吡咯与酒石酸基醛的乙烯基Mukaiyama aldol反应的非对映选择性，并将其作为合成栗精胺的模型反应。与-PMB或-Bn和4-甲氧基的组合，反应产生的羟醛加合物的C-8和C-8a的吲哚里西啶生物碱栗精胺的正确的绝对构型。加合物转化为indolizidine，其缩酮不能适当地转化为目标alkaloid.Conclusion：第一次成功的非对映选择性Mukaiyama羟醛策略的C-8和C-8a立体异构中心的栗精胺使用silyloxypyrrole化学。结果表明，一个完整的对映选择性合成可以实现提供C-I官能化是在合成早期完成，后耦合。
Background: The diastereoselectivity of a vinylogous Mukaiyama aldol reaction of a series of N-substituted 4-oxy-2-trimethylsilyloxypyrroles with a tartrate-based aldehyde has been explored as a model reaction for castanospermine synthesis.Results: The study has revealed that the reaction is sensitive to the nature of the combination of - and 4-oxy substituents. With a -PMB or -Bn and 4-methoxy combination, the reaction generates an aldol adduct with the correct absolute configurations for C-8 and C-8a of the indolizidine alkaloid castanospermine. The adduct was transformed to an indolizidine, whose ketal could not be transformed appropriately for the target alkaloid.Conclusion: The first successful diastereoselective Mukaiyama aldol strategy for the C-8 and C-8a stereogenic centres of castanospermine is presented using silyloxypyrrole chemistry. The results suggest that a full enantioselective synthesis can be realized provided that C-I functionalisation is accomplished early in the synthesis, post-coupling.