Direct Titanium-Mediated Conversion of Ketones into Enamides with Ammonia and Acetic Anhydride
作者:Jonathan T. Reeves、Zhulin Tan、Zhengxu S. Han、Guisheng Li、Yongda Zhang、Yibo Xu、Diana C. Reeves、Nina C. Gonnella、Shengli Ma、Heewon Lee、Bruce Z. Lu、Chris H. Senanayake
DOI:10.1002/anie.201107601
日期:2012.2.6
A one‐step conversion of ketones into N‐acetyl enamides was developed. The process employs safe and inexpensive reagents, proceeds under mild conditions, and tolerates diverse functional groups. The addition of edte (N,N,N′,N′‐tetrakis(2‐hydroxyethyl)ethylenediamine) prior to workup enables water solubilization of Ti alkoxides and allows a simple extractive workup.
Catalytic Asymmetric Access to Noncanonical Chiral α-Amino Acids from Cyclic Iminoglyoxylates and Enamides
作者:Yue Zhang、Jun-Kuan Li、Fa-Guang Zhang、Jun-An Ma
DOI:10.1021/acs.joc.0c00436
日期:2020.4.17
Mannich reaction of cyclic iminoglyoxylates with enamides by virtue of chiral phosphoric acid catalysis in a one-pot manner. The wide substrate scope, mild reaction conditions, and constantly excellent enantioselectivities (>95% ee in most cases) render this protocol highly practical for the rapid construction of valuable noncanonical chiral α-amino-acid building blocks.
Chiral Phosphoric Acid‐Catalyzed Enantioselective Formal [4+2] Cycloaddition Between Dienecarbamates and 2‐Benzothioazolimines
作者:Wei‐Yang Ma、Emeric Montinho‐Inacio、Bogdan I. Iorga、Pascal Retailleau、Xavier Moreau、Luc Neuville、Géraldine Masson
DOI:10.1002/adsc.202200161
日期:2022.5.17
cycloaddition between 2-benzothiazolimines and N-H-1,3-dienecarbamates is described. A divergence in reaction pathways was observed depending on the dienes employed. The reaction performed with 4-substituted dienes produced benzothiazolopyrimidines as major product in yields ranging from 42 to 67%, as single diastereoisomer and with enantioselectivity between 93 and 99%. The same reaction performed with
Catalyst-free and oxidant-free tandem aza-Mannich/cyclization/aromatization of <i>C</i>,<i>N</i>-cyclic azomethine imines with enamides: facile synthesis of 5,6-dihydropyrazolo[5,1-<i>a</i>]isoquinolines
作者:Hao Dong、Yongxing Zhang、Xiaochen Tian、Ruochen Pang、Weiwu Ren、Yang Wang
DOI:10.1039/d2gc01275h
日期:——
tandem aza-Mannich/cyclization/aromatization reaction of C,N-cyclic azomethine imines with enamides has been developed. This practical one-step protocol enables a simple and environmentally friendly route toward the straightforward synthesis of highly substituted 5,6-dihydropyrazolo[5,1-a]isoquinolines. Different types of enamides and enamines, especially enamides derived from marketed drugs as well as bioactive
开发了一种新型高效的无催化剂、无氧化剂串联氮杂曼尼希/环化/芳构化C , N-环偶氮甲亚胺与烯酰胺反应。这种实用的一步法为直接合成高度取代的 5,6-二氢吡唑并[5,1- a ] 异喹啉提供了一种简单且环保的途径。不同类型的烯酰胺和烯胺,尤其是衍生自上市药物以及生物活性分子的烯酰胺,是合适的底物。CB1 大麻素受体拮抗剂可以基于该方法有效合成,说明这将是合成有价值的结构基序的实用策略。
Organocatalytic Enantioselective Diels–Alder Reaction of 2‐Trifluoroacetamido‐1,3‐dienes with α,β‐Unsaturated Ketones
作者:Xin‐Qi Zhu、Qian Wang、Jieping Zhu
DOI:10.1002/anie.202214925
日期:2023.1.2
CPA-catalyzed annulation of 2-trifluoroacetamido-1,3-dienes with α,β-unsaturated carbonyl compounds affords highly functionalized 1-trifluoroacetamido cyclohex-1-ene derivatives 3 in high yields with excellent diastereo- and enantioselectivities. An asymmetric three-component reaction of 1, 2 and ortho-hydroxybenzhydryl alcohols 4 provides the densely functionalized hexahydroxanthenes with concurrent