Nair Vijay, Vellalath Sreekumar, Babu Beneesh Pattoorpadi
Organic Chemistry Section, NIIST-CSIR (Formerly Regional Research Laboratory), Trivandrum 695 019, India.
Chem Soc Rev. 2008 Dec;37(12):2691-8. doi: 10.1039/b719083m. Epub 2008 Oct 21.
Homoenolate, a species containing anionic carbon beta to a carbonyl group or a moiety that can be transformed into a carbonyl group, is a potential three carbon synthon. Recent introduction of a protocol for the generation of homoenolate directly from enals by NHC (nucleophilic heterocyclic carbene) catalysis has made it possible to explore the synthetic utility of this unique reactive intermediate. The versatility of NHC-bound homoenolate is illustrated by its annulation with various carbonyl compounds leading to gamma-butyrolactones, spiro-gamma-butyrolactones, and delta-lactones. Interception of homoenolate with imines afforded gamma-lactams and bicyclic beta-lactams. Formation of cyclopentenes and spirocyclopentanones respectively by reaction with enones and dienones is also noteworthy. This tutorial review focuses on these and other types of reactions which attest to the synthetic potential of NHC-bound homoenolates in organic synthesis.
同烯醇盐是一种在羰基β位含有阴离子碳的物种，或者是一种可以转化为羰基的部分，它是一种潜在的三碳合成子。最近通过NHC（亲核杂环卡宾）催化直接从烯醛生成同烯醇盐的方法的引入，使得探索这种独特反应中间体的合成效用成为可能。与各种羰基化合物环化生成γ-丁内酯、螺环-γ-丁内酯和δ-内酯，说明了与NHC结合的同烯醇盐的多功能性。同烯醇盐与亚胺的反应生成了γ-内酰胺和双环β-内酰胺。与烯酮和二烯酮反应分别形成环戊烯和螺环环戊酮也值得注意。本教程综述重点关注这些以及其他类型的反应，这些反应证明了与NHC结合的同烯醇盐在有机合成中的合成潜力。
