Switchable Access to Different Spirocyclopentane Oxindoles by N-Heterocyclic Carbene Catalyzed Reactions of Isatin-Derived Enals and N-Sulfonyl Ketimines
fused spirocyclopentane oxindoles with four contiguousstereocenters, including twoquaternary carbon centers, was developed. Alternatively, spirocyclopentane oxindoles containing an enaminone moiety can be achieved using the same starting materials, isatin‐derived enals, and N‐sulfonyl ketimines, in the presence of a slightly different NHC catalytic system. This switchable annulation strategy enables
Enantioselective Activation of Stable Carboxylate Esters as Enolate Equivalents <i>via</i> N-Heterocyclic Carbene Catalysts
作者:Lin Hao、Yu Du、Hui Lv、Xingkuan Chen、Huishen Jiang、Yaling Shao、Yonggui Robin Chi
DOI:10.1021/ol300676w
日期:2012.4.20
The first N-Heterocyclic Carbene (NHC) mediated activation of stable carboxylate esters to generate enolate intermediates is disclosed. The catalytically generated arylacetic ester enolates undergo enantioselective reactions with α,β-unsaturated imines.
Copper-catalyzed conjugate protosilylation reaction of α,β-unsaturated sulfonyl ketimines has been developed. The corresponding E- and Z-stereoselective functionalized allylsilane products were obtained in good yields respectively via tuning the ligands used in the reactions. Furthermore, the highly enantioselective (E)-β-tosylamine-substituted allylsilanes were also achieved in the presence of chiral
DMAP-promoted in situ activation of bromoacetic acid as a 2-carbon synthon for facile synthesis of pyridines and fused pyridin-2-ones
作者:Lu Wang、Gaoyuan Zhu、Weifang Tang、Tao Lu、Ding Du
DOI:10.1016/j.tet.2016.08.062
日期:2016.10
A general and simple synthesis of 2,4,6-trisubstituted pyridines and fused pyridine-2-ones from bromoacetic acid is developed via a DMAP-promoted in situ activation strategy. In this protocol, readily accessible bromoacetic acid has been effectively employed as a 2C synthon to undergo formal [2+4] cycloadditions with diverse acyclic and cyclic 1-azadienes. Low costs of the reagents and materials, mild
Sterically and Temperature Controlled Divergent Cycloadditions of α,β‐Unsaturated Imines with Vinylethylene Carbonates: Insights from Experimental and DFT Studies
作者:Xiaolong Xie、Dandan Yuan、Ben Ma、Jiaming Jin、Enpeng Wang、Wenyi Zhou、Yaowen Hu、Lihong Hu、Junwei Wang
DOI:10.1002/adsc.202101423
日期:2022.3.15
Divergent synthesis of heterocycles with controllable ring sizes from the same starting materials is a long-standing challenge. We report herein the first example of controllable divergent [4+5] and [2+3] cycloadditions of α,β-unsaturatedimines and vinylethylene carbonates, which enables the selectively synthesis of nine-membered and different five-membered heterocycles by controlling the reaction