Heterocycles via intramolecular platinum-catalyzed propargylic substitution
摘要:
We report a Pt(II)-catalyzed cyclization of nucleophile-tethered propargylic acetates yielding substituted heterocycles containing multiple heteroatoms including morpholines, dioxanes, and sulfamates with high cis-selectivity. (C) 2011 Elsevier Ltd. All rights reserved.
KOAc-promoted alkynylation of α-C–H bonds of ethers with alkynyl bromides under transition-metal-free conditions
作者:Jiajun Zhang、Pinhua Li、Lei Wang
DOI:10.1039/c4ob00002a
日期:——
KOAc-promoted α-position C–H activation and alkynylation of ethers with alkynyl bromides to 2-alkynyl ethers was developed under transition-metal-free conditions.
Decatungstate as Direct Hydrogen Atom Transfer Photocatalyst for SOMOphilic Alkynylation
作者:Luca Capaldo、Davide Ravelli
DOI:10.1021/acs.orglett.1c00381
日期:2021.3.19
A versatile approach for the alkynylation of a variety of aliphatic hydrogen donors, including alkanes, is reported. We used tetrabutylammonium decatungstate as photocatalyst to generate organoradicals from C–H/Si–H bondsvia hydrogen atom transfer. The latter intermediates underwent SOMOphilic alkynylation by methanesulfonyl alkynes to afford internal alkynes upon loss of a sulfonyl radical. The effect
A metal-free direct alkylation of CâH bonds adjacent to an oxygen or nitrogen atom was developed. This reaction occurred between saturated heterocycles and ethynylbenziodoxolones under mild conditions. A series of 2-alkynyl cyclic alkanes that contain oxygen or nitrogen atoms were prepared in moderate to good yields.
Photochemical Functionalization of Heterocycles with EBX Reagents: C−H Alkynylation versus Deconstructive Ring Cleavage**
作者:Errika Voutyritsa、Marion Garreau、Maroula G. Kokotou、Ierasia Triandafillidi、Jérôme Waser、Christoforos G. Kokotos
DOI:10.1002/chem.202002868
日期:2020.11.11
The development of novel methodologies for the functionalization of saturated heterocycles is highly desirable. Herein, we report a cheap and efficient photochemical method for the C−H functionalization of saturated O‐heterocycles, as well as the deconstructive ring‐cleavage of S‐heterocycles, employing hypervalent iodine alkynylation reagents (ethynylbenziodoxolones, EBX). This photochemical alkynylation
Visible‐Light‐Induced Alkynylation of α‐C–H Bonds of Ethers with Alkynyl Bromides without External Photocatalyst
作者:Xiaofei Xie、Jie Liu、Lei Wang、Min Wang
DOI:10.1002/ejoc.201900872
日期:2020.3.15
An unprecedented direct alkynylation reaction of α‐C(sp3)–H bonds of ethers under visiblelight irradiation at room temperature withoutexternalphotocatalyst was developed.