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
Organocatalytic Activation of Alkylacetic Esters as Enolate Precursors to React with α,β-Unsaturated Imines
作者:Lin Hao、Shaojin Chen、Jianfeng Xu、Bhoopendra Tiwari、Zhenqian Fu、Tong Li、Jieyan Lim、Yonggui Robin Chi
DOI:10.1021/ol4021805
日期:2013.10.4
Asymmetric functionalization of alkylacetic esters and their derivatives is traditionally achieved via preformed enolates with chiral auxiliaries. Catalytic versions of such transformations are attractive but challenging. A direct catalytic activation of simple alkylacetic esters via N-heterocyclic carbene organocatalysts to generate chiral enolate intermediates for highly enantioselective reactions is reported.