Formal [3 + 4] Annulation of α,β-Unsaturated Acyl Azoliums: Access to Enantioenriched N–<i>H</i>-Free 1,5-Benzothiazepines
作者:Chao Fang、Tao Lu、Jindong Zhu、Kewen Sun、Ding Du
DOI:10.1021/acs.orglett.7b01457
日期:2017.7.7
An unprecedented formal [3 + 4] annulation of α,β-unsaturatedacyl azoliums with 2-aminobenzenethiols has been utilized to synthesize enantioenriched N–H-free 1,5-benzothiazepines, which are recognized as privileged structures in numerous biologically active scaffolds. This protocol offers a rapid and direct pathway to access the target compounds with high enantioselectivities and has been applied
N-Heterocyclic carbene-catalyzed [3+3] cyclocondensation of bromoenals with aldimines: highly enantioselective synthesis of dihydropyridinones
作者:Zhong-Hua Gao、Xiang-Yu Chen、Han-Ming Zhang、Song Ye
DOI:10.1039/c5cc04593b
日期:——
The N-heterocycliccarbene-catalyzed [3+3] cyclocondensation of bromoenals with aldimines was developed to give the corresponding dihydropyridinones in good yields with excellent enantioselectivies.
Conjugated Dienyne‐Imides as Robust Precursors of 1‐Azatrienes for 6π Electrocyclizations to Furo[2,3‐
<i>b</i>
]dihydropyridine Cores
作者:Yanjun Wan、Xuchun Zheng、Cheng Ma
DOI:10.1002/anie.201800303
日期:2018.5.4
intermediates for 6πelectrocyclizations was developed by using readily accessible dienyne‐imides and various terminal olefins under PdII catalysis. Taking advantage of the sequential cooperation between preloaded and incorporated functional handles at 1,3‐dien‐5‐yne skeletons, this method not only enables the selective generation of putative 1‐azatrienes but significantly accelerates their thermal 6π‐electrocyclic
通过在Pd II催化下使用易得的二烯炔-酰亚胺和各种末端烯烃,开发了一种新的策略来生成用于6π电环化的功能化1-氮杂三烯中间体。利用这种方法,可以在1,3-dien-5-yne骨架上预先加载和合并功能手柄之间的顺序配合,不仅可以选择性地生成假定的1-氮杂氮杂环丁烷,而且还可以显着加速其6π-电热环闭环反应的过程。一系列高产率的呋喃[2,3- b ]二氢吡啶衍生物。
Carbene-Catalyzed Enantioselective Addition of Thioamides to Bromoenals for Access to Thiazinone Heterocycles
作者:Changyi Liu、Shuquan Wu、Jun Xu、Lingzhu Chen、Pengcheng Zheng、Yonggui Robin Chi
DOI:10.1021/acs.orglett.9b03685
日期:2019.12.6
steps include enantioselective 1,4-addition of thioamide sulfur atoms to α,β-unsaturatedacylazolium intermediate. Subsequent intramolecular annulation eventually affords thiazinone heterocycles with high optical purities. The introduction of Lewis acid additives such as Cu(OTf)2 to this NHC catalytic reaction could provide small but consistent improvements to reaction enantioselectivities.
N-Heterocyclic Carbene-Catalyzed Enantioselective Annulation of Bromoenal and 1,3-Dicarbonyl Compounds
作者:Fang-Gang Sun、Li-Hui Sun、Song Ye
DOI:10.1002/adsc.201100622
日期:2011.11
Highly enantioselective [3+3] annulation reactions of bromoenals and 1,3-dicarbonylcompounds are reported. In addition, both enantiomers of the resultant dihydropyranone could be easily obtained by choosing N-heterocyclic carbenes (NHCs) with the same stereocenter but different substituents under the optimized reaction conditions.