Synthesis of Bridged Azacycles and Propellanes via Nitrene/Alkyne Cascades
作者:Qinxuan Wang、Jeremy A. May
DOI:10.1021/acs.orglett.0c00798
日期:2020.4.17
nitrene tether showed that 7-membered rings were the maximum ring size to be formed by nitrene attack on the alkyne. Examples incorporating stereocenters on the carbonazidate’s tether induced diasteroselectivity in the formation of the bridgedring and two new stereocenters. Additionally, propellanes containing aminals, hemiaminals, and thioaminals formed from the bridged azacycles in the same reaction via
Metal-Free Three-Component Oxyalkynylation of Alkenes
作者:Yangshan Li、Ran Lu、Shutao Sun、Lei Liu
DOI:10.1021/acs.orglett.8b02954
日期:2018.11.2
An unprecedented (NH4)2S2O8 mediated metal-free three-componentalkene oxyalkynylation using H2O or alcohol as oxygenation agent is described. Mechanistic studies suggested that the reversed regioselectivity should be dictated by an alkene radical cation intermediate.
描述了前所未有的(NH 4)2 S 2 O 8介导的使用H 2 O或醇作为氧化剂的无金属三组分链烯氧基炔基化反应。机理研究表明,逆向的区域选择性应由烯烃自由基阳离子中间体决定。
Csp–Csp<sup>3</sup> Bond Formation via Iron(III)-Promoted Hydroalkynylation of Unactivated Alkenes
作者:Yangyong Shen、Bo Huang、Jing Zheng、Chen Lin、Yu Liu、Sunliang Cui
DOI:10.1021/acs.orglett.7b00499
日期:2017.4.7
An iron(III)-promoted hydroalkynylation of unactivated alkenes toward Csp–Csp3 bond formation has been developed. Various alkenes, including mono-, di-, and trisubstituted alkenes, could all smoothly convert to structural diversified alkynes in this chemoselective protocol. Additionally, the scalability was unraveled and the further divergent transformations of products were conducted to demonstrate
Metal-Free Synthesis of Homopropargylic Alcohols from Aldehydes
作者:Bruno V. M. Teodoro、Luiz F. Silva
DOI:10.1021/acs.joc.7b01629
日期:2017.11.17
This transformation is based on a one-pot procedure involving sequential α-alkynylation of acyclic aldehydes using hypervalent iodine reagents and borohydride reduction. The chemistry exhibits broad substrate scope and good scalability, providing a convenient route for the α-alkynylation of aldehydes along with the formation of a quaternary carbon center. The applicability of the method is demonstrated
Rh(II)-Catalyzed Chemoselective Oxidative Amination and Cyclization Cascade of 1-(Arylethynyl)cycloalkyl)methyl Sulfamates
作者:Dong Pan、Yin Wei、Min Shi
DOI:10.1021/acs.orglett.7b01558
日期:2017.7.7
A Rh(II)-catalyzed chemoselective oxidative amination and cyclization cascade of 1-(arylethynyl)cycloalkyl)methyl sulfamates has been presented. For a cyclopropyl or cyclobutyl moiety containing alkynyl sulfamates, the reactions underwent a metallonitrene-initiated alkyne oxidation along with cyclopropyl ring expansion or alkoxyl moiety migration to give cyclobutane-fused or methylenecyclobutane-containing