N-heterocyclic carbene-catalyzed generation of homoenolates:: γ-butyrolactones by direct annulations of enals and aldehydes
N-heterocyclic carbene-catalyzed generation of homoenolates:: γ-butyrolactones by direct annulations of enals and aldehydes
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DOI：
10.1021/ja044714b
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发表时间：
2004-11-10
影响因子：
15
通讯作者：
Bode, JW
中科院分区：
文献类型：
--
作者：
Sohn, SS;Rosen, EL;Bode, JW
以二芳咪唑盐原位制备n -杂环碳烯，作为α，β-不饱和醛生成反应性高烯醇酯的高效催化剂。催化剂结合的同烯酸酯与亲电醛反应，通过活化羧酸盐的关键中间体，以良好的收率和立体选择性生成γ-丁内酯。重要的是，该过程展示了在异常温和和方便的反应条件下，使用多功能有机催化剂生成亲核碳离子的前所未有的反应模式。
N-Heterocyclic carbenes, prepared in situ from diarylimidazolium salts, serve as highly effective catalysts for the generation of reactive homoenolates from α,β-unsaturated aldehydes. The catalyst-bound homoenolate reacts with electrophilic aldehydes leading, via the key intermediacy of an activated carboxylate, to γ-butyrolactones in good yields and stereoselectivities. Importantly, this process demonstrates an unprecedented reaction mode for the generation of nucleophilic carbanions with a multifunctional organocatalyst under exceptionally mild and convenient reaction conditions.