Radical Enamination of Vinyl Azides: Direct Synthesis of N-Unprotected Enamines
摘要:
An electron-withdrawing-group-generable radical-induced enamination of vinyl azides is reported, which results in a variety of beta-functionalized N-unprotected enamines in a stereoselective manner. A plausible mechanism involving an unusual 1,3-H transfer of in situ generated iminyl radical intermediate was proposed on the basis of experimental results and DFT calculations.
AgN<sub>3</sub>-Catalyzed Hydroazidation of Terminal Alkynes and Mechanistic Studies
作者:Shanshan Cao、Qinghe Ji、Huaizhi Li、Maolin Pang、Haiyan Yuan、Jingping Zhang、Xihe Bi
DOI:10.1021/jacs.0c00836
日期:2020.4.15
hydroazidation of alkynes is the most straightforward way to access vinyl azides - versatile building blocks in organic synthesis. We previously realized such a fundamental reaction of terminalalkynes using Ag2CO3 as a catalyst. However, the high catalyst loading seriously limits its practicality, and moreover the exact reaction mechanism remains unclear. Here, on the basis of X-ray diffraction studies on the
Interruption of Formal Schmidt Rearrangement/Hosomi–Sakurai Reaction of Vinyl Azides with Allyl/Propargylsilanes
作者:Guichun Fang、Zhenhua Liu、Shanshan Cao、Haiyan Yuan、Jingping Zhang、Ling Pan
DOI:10.1021/acs.orglett.8b03062
日期:2018.11.16
An interrupted Schmidt rearrangement/Hosomi–Sakurai reaction of N-tosyl and S-substituted vinyl azides is reported. With BF3·Et2O as a Lewis acid promoter, the denitrogenative fragmentation of vinyl azides facilitates the generation of the N/S-stabilized carbocations, which further undergo nucleophilic addition by allyl/propargylsilanes for C–C bond formation. As a result, a variety of homoallylic/allenylic
Visible-Light-Driven Synthesis of 4-Alkyl/Aryl-2-Aminothiazoles Promoted by In Situ Generated Copper Photocatalyst
作者:Wen-Long Lei、Tao Wang、Kai-Wen Feng、Li-Zhu Wu、Qiang Liu
DOI:10.1021/acscatal.7b02818
日期:2017.11.3
Room-temperature synthesis of 4-alkyl/aryl-2-aminothiazoles from vinyl azides and ammonium thiocyanate was accomplished with the aid of copper salts and blue LED irradiation. Mechanism investigation indicates that in situ-formed Cu(NCS)2– plays dual important roles in the reaction: (1) as the photocatalyst to activate vinyl azides, (2) as the Lewis acid catalyst to promote ring opening of 2H-azirines