All-Carbon (4+2) Annulations Catalysed by N-Heterocyclic Carbenes
All-Carbon (4+2) Annulations Catalysed by N-Heterocyclic Carbenes
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DOI：
10.1055/s-0036-1588109
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发表时间：
2017-04-01
期刊：
影响因子：
2
通讯作者：
Lupton, David W.
中科院分区：
文献类型：
--
作者：
Levens, Alison;Lupton, David W.
不到五年前，我们报道了NHC催化的二烯醇醚和不饱和酰氟的（4+2）成环反应。从机理的角度来看，该反应可能涉及乙烯基迈克尔加成，随后是羟醛/β-内酯化级联。在这个帐户中，这个反应的发现和随后的研究，其机制和多步合成的效用将被检查。随后开发的手性催化剂设计用于该反应和实现的第一代和后来的第二代方法，该反应的对映选择性的变体将被讨论。最后，将介绍导致苯甲醛的相关氧化还原异构化级联，以及利用类似反应过程的NHC催化领域中的反应。1引言2反应设计和发现3机理研究和β-内酯拦截4对映选择性环己烯基β-内酯合成5对映选择性环己二烯合成6氧化还原异构化7相关NHC催化8结论
Less than five years ago we reported the NHC-catalysed (4+2) annulation of dienol ethers and unsaturated acyl fluorides. From a mechanistic perspective, this reaction likely involves a vinylogous Michael addition followed by an aldol/beta-lactonisation cascade. In this account, the discovery of this reaction and ensuing studies into its mechanism and utility in multistep synthesis will be examined. The subsequent development of chiral catalysts designed for this reaction and the achievement of a first-generation and later second-generation approach to an enantioselective variant of this reaction will be discussed. Finally, related redox isomerisation cascades leading to benzaldehydes will be introduced, as will reactions in the field of NHC catalysis that exploit similar reaction cascades.1 Introduction2 Reaction Design and Discovery3 Mechanistic Studies and beta-Lactone Interception4 Enantioselective Cyclohexenyl beta-Lactone Synthesis5 Enantioselective Cyclohexadiene Synthesis6 Redox Isomerisation7 Related NHC Catalysis8 Conclusions