Intramolecular ipso-Halocyclization of 4-(p-Unsubstituted-aryl)-1-alkynes Leading to Spiro[4,5]trienones: Scope, Application, and Mechanistic Investigations
摘要:
A new, general method for the synthesis of spiro[4,5]trienores is described by the intramolecular ipso-halocyclization of 4-(p-unsubstituted-aryl)-1-alkynes. In the presence of halide electrophiles, a variety of 4-(p-unsubstituted-aryl)-1-alkynes underwent the intramolecular ipso-halocyclization with water smoothly, affording the corresponding halo-substituted spiro[4,5]trienones in moderate to good yields. The obtained spiro[4,5]trienones can be applied in constructing the azaquaternary tricyclic skeleton via Pd-catalyzed Heck reaction. Notably, the prepared spiro[4,5]trienones and azaquaternary tricycles are of importance in the areas of pharmaceuticals and agrochemicals. The mechanism of the intramolecular ipso-halocyclization reaction is also discussed according to the O-18-labeling experiments and DFT calculations.
Visible-light-mediated selective thiocyanation/ipso-cyclization/oxidation cascade for the synthesis of thiocyanato-containing azaspirotrienediones
作者:Yuan Chen、Yu-Jue Chen、Zhi Guan、Yan-Hong He
DOI:10.1016/j.tet.2019.130763
日期:2019.12
visible-light-mediated metal-free thiocyanate radicaladdition/ipso-cyclization/oxidation cascade reaction for the synthesis of thiocyanato-containing azaspirotrienediones from N-phenylpropynamides is described. Cheap and readily available ammonium thiocyanate was used as a precursor to the thiocyanate freeradical, which undergoes a radicaladditionreaction with the alkyne, followed by selective ipso-cyclization
Silver-catalyzed direct spirocyclization of alkynes with thiophenols: a simple and facile approach to 3-thioazaspiro[4,5]trienones
作者:Huanhuan Cui、Wei Wei、Daoshan Yang、Jimei Zhang、Zhihong Xu、Jiangwei Wen、Hua Wang
DOI:10.1039/c5ra16548b
日期:——
A new and convenient silver-catalyzed direct oxidative spirocyclization of alkynes with thiophenols is described. This methodology provides a simple and practical approach to various 3-thioazaspiro[4,5]trienones in moderate to good yields with high atom efficiency and excellent functional group tolerance.
Access to 3‐(2‐Oxoalkyl)‐azaspiro[4.5]trienones
<i>via</i>
Acid‐Triggered Oxidative Cascade Reaction through Alkenyl Peroxide Radical Intermediate
作者:Chang‐Sheng Wang、Thierry Roisnel、Pierre H. Dixneuf、Jean‐François Soulé
DOI:10.1002/adsc.201801203
日期:2019.2
Azaspiro[4.5]trienones bearingketone side chains at the 3‐position are prepared from N‐alkyl‐arylpropiolamides and ketones via oxidative 1,2‐difunctionalization of alkynes. The cascade sequence starts with the generation of alkenyl peroxide intermediates, which are obtained by addition of tert‐butyl hydroperoxide to ketones in presence of a catalytic amount of a strong acid. Then, the ketone radical adds to
Palladium Nanoparticle-Catalyzed Stereoselective Domino Synthesis of All-Carbon Tetrasubstituted Olefin Containing Oxindoles via Carbopalladation/C–H Activation
作者:Naziya Parveen、Govindasamy Sekar
DOI:10.1021/acs.joc.0c00915
日期:2020.8.21
catalyzed single-step, stereoselective domino synthesis of symmetrically and unsymmetrically all-carbon tetrasubstituted olefin containing oxindoles from readily accessible anilides has been developed. The Pd-BNP catalyst showed a wide range of functional group tolerance that enabled building a library of heteroaromatics. This reusable Pd catalyst reflected its utility in the synthesis of biologically important
Palladium‐Catalyzed 5‐
<i>exo‐dig</i>
Cyclization Cascade, Sequential Amination/Etherification for Stereoselective Construction of 3‐Methyleneindolinones
An cascade intramolecular 5‐exo‐dig cyclization of N‐(2‐iodophenyl)propiolamides and sequential amination/etherification (with N‐hydroxybenzamides, phenyl hydroxycarbamate) protocol for the synthesis of amino‐ and phenoxy‐substituted 3‐methyleneindolinones using unexpensive Pd(PPh3)4 as catalyst has been developed. The protocol enables the assembly of structurally important oxindole cores featuring