Regio- and stereoselective synthesis of (E)-β-halo alkenyl ketones/sulfones via haloallylation of alkynyl ketones/sulfones
摘要:
An atom-economic protocol to the regio- and stereoselective formation of tetrasubstituted alkenyl ketones/sulfones is realized via the Pd-catalyzed haloallylation of alkynyl ketones/sulfones, which provides an efficient and straightforward pathway to synthesis highly functionalized alkenes. (c) 2015 Published by Elsevier Ltd.
“Anti-Michael addition” of Grignard reagents to sulfonylacetylenes: synthesis of alkynes
作者:Francisco Esteban、Lazhar Boughani、José L. García Ruano、Alberto Fraile、José Alemán
DOI:10.1039/c7ob00783c
日期:——
In this work, the addition of Grignardreagents to arylsulfonylacetylenes, which undergoes an “anti-Michael addition”, resulting in their alkynylation under very mild conditions is described. The simplicity of the experimental procedure and the functional group tolerance are the main features of this methodology. This is an important advantage over the use of organolithium at −78 °C that we previously
Expanding the Scope of Arylsulfonylacetylenes as Alkynylating Reagents and Mechanistic Insights in the Formation of Csp<sup>2</sup>Csp and Csp<sup>3</sup>Csp Bonds from Organolithiums
作者:José Luis García Ruano、José Alemán、Leyre Marzo、Cuauhtémoc Alvarado、Mariola Tortosa、Sergio Díaz‐Tendero、Alberto Fraile
DOI:10.1002/chem.201200939
日期:2012.7.2
We describe the unexpected behavior of the arylsulfonylacetylenes, which suffer an “anti‐Michael” addition of organolithiums producing their alkynylation under very mild conditions. The broad scope, excellent yields, and simplicity of the experimental procedure are the main features of this methodology. A rational explanation of all these results can be achieved by theoretical calculations, which suggest
Nickel-catalyzed cross-coupling reaction of acetylenic sulfones with alkynyl Grignard reagents: a facile method for the preparation of unsymmetrical 1,3-diynes
作者:Kuang Fang、Meihua Xie、Zhannan Zhang、Peng Ning、Guanying Shu
DOI:10.1016/j.tetlet.2013.05.049
日期:2013.7
The cross-coupling reaction of acetylenic sulfones with acetylenic Grignardreagents was realized by using Ni(acac)2 as catalyst to afford unsymmetrical 1,3-diynes under mild conditions without homocoupling byproducts. By using this method, 1,4-diaryl-1,3-diynes could be obtained in moderate to good yields (59–83%), whereas, the yields for alkyl substituted 1,3-diynes are lower (30–54%).
Redox-Activated Amines in C(<i>sp</i><sup>3</sup>)–C(<i>sp</i>) and C(<i>sp</i><sup>3</sup>)–C(<i>sp</i><sup>2</sup>) Bond Formation Enabled by Metal-Free Photoredox Catalysis
作者:Michał Ociepa、Joanna Turkowska、Dorota Gryko
DOI:10.1021/acscatal.8b03437
日期:2018.12.7
one of the most prevalent structural motifs in organic chemistry. Therefore, application of amines as alkylating agents in synthesis is highly compelling. Herein, we present a metal-free photoredox strategy for the formation of C(sp3)–C(sp) and C(sp3)–C(sp2) bonds from redox-activated primary aminederivatives. The developed reaction of 2,4,6-triphenylpyridinium salts with alkynyl p-tolylsulfones, leading
Highly Stereoselective Synthesis of Tertiary Propargylic Centers and Their Isomerization to Enantiomerically Enriched Allenes
作者:José Luis García Ruano、Leyre Marzo、Vanesa Marcos、Cuauhtémoc Alvarado、José Alemán
DOI:10.1002/chem.201201607
日期:2012.8.6
Center of attention: A new approach for the synthesis of enantiomericallyenriched allenes by isomerization of 2‐p‐tolylsulfinylphenyl propargylic derivatives is presented, which in turn are prepared by reaction of sulfinylated lithium benzylcarbanions with arylsulfonylacetylenes (see scheme). The high control of stereoselectivity in both steps is exerted by the sulfinyl group.