Ultrasound Promoted ‘One Pot’ Conversion of Nitrocompounds to Carbamates
作者:S. Chandrasekhar、Ch. Narsihmulu、V. Jagadeshwar
DOI:10.1055/s-2002-25338
日期:——
An efficient ultrasound promoted novel direct conversion of nitro compounds to N-(tert-butoxycarbonyl) amines and N-(ethoxycarbonylamines) is achieved using Sn-NH4Cl for the first time.
Access to 5,6-Spirocycles Bearing Three Contiguous Stereocenters via Pd-Catalyzed Stereoselective [4 + 2] Cycloaddition of Azadienes
作者:Siti Nur Fairuz Binte Sheikh Ismail、Binmiao Yang、Yu Zhao
DOI:10.1021/acs.orglett.1c00505
日期:2021.4.16
[4 + 2] cycloaddition of benzofuran-derived azadienes with vinyl benzoxazinanones, which represents a rare highly stereoselective cycloaddition of this class of fused azadienes as a two-atom synthon. The use of a phosphoramidite ligand bearing a chiral secondary amine with a simple biphenyl backbone proved to be the key to construct the novel spirocyclic tetrahydroquinoline scaffold containing three
1,6-Dipolar cycloadditions represent a valuable strategy for the rapid construction of medium-sized rings. Herein, we describe the concept for the design of 1,6-dipoles that bypasses the regioselectivity. Through the introduction of an amino group into Morita–Baylis–Hillman (MBH) carbonates, unprecedented [6 + 2] dipolarcycloadditions were accurately developed with Cs2CO3, efficiently delivering a
Construction of a Benzo[<i>b</i>]azepine Skeleton through Decarboxylative Ylide [6+1] Annulations with Modified Vinyl Benzoxazinanones
作者:Qing-Zhu Li、Zhi-Qiang Jia、Lin Chen、Xiang Zhang、Hai-Jun Leng、Rong Zeng、Yan-Qing Liu、Wen-Lin Zou、Jun-Long Li
DOI:10.1021/acs.orglett.0c04041
日期:2021.2.5
A Lewis acid-promoted [6+1] annulation between sulfur ylides and modified vinyl benzoxazinanones was described. In this reaction, the newly designed vinyl benzoxazinanones could serve as a novel six-atom synthon, and the key to success is the installation of an electron-withdrawing group on the alkene moiety of the benzoxazinanones. A broad range of substrates are compatible with this mild reaction
描述了路易斯酸促进硫基化物和改性乙烯基苯并恶嗪酮之间的[6 + 1]环化。在该反应中,新设计的乙烯基苯并恶嗪酮可以用作新型的六原子合成子,成功的关键是在苯并恶嗪酮的烯烃部分上安装了一个吸电子基团。各种各样的底物都与这种温和的反应体系兼容,从而为构建苯并[ b ]氮杂骨架提供了简便实用的方法。
DABCO catalyzed [4+2] annulations of Morita–Baylis–Hillman carbonates with isocyanates
作者:Wei Cai、Yiming Zhou、Yanlin He、You Huang
DOI:10.1039/d1cc03502a
日期:——
A highly concise method for 1,4-diazabicyclo[2.2.2]octane (DABCO) catalyzed [4+2] annulations of o-amino-acylation of aryl MBH carbonates with isocyanates has been developed. For the first time, MBH carbonates served as 1,4-dipoles, providing functionalized 3,4-dihydroquinazolinones in mild conditions with good to excellent yields. The density functional theory calculations of the mechanism supports