Microwave assisted metal-/oxidant-free cascade electrophilic sulfenylation/5-endo-dig cyclization of 2-alkynylanilines to generate diversified 3-sulfenylindoles
摘要:
A metal-/oxidant-free sustainable protocol for the synthesis of 3-sulfenylindoles based on electrophilic cyclization of 2-alkynylanilines has been developed under microwave irradiation. Herein, catalytic amount of iodine and stoichiometric amount of sulfonyl hydrazides were employed as catalyst and electrophiles respectively to induce the 5-endo-dig cyclization of 2-alkynylanilines. This strategy allows a wide substrate scope, demonstrates good functional group tolerance, utilizes easily available reagents and overcome multistep synthesis. (C) 2017 Elsevier Ltd. All rights reserved.
3-Sulfenylindoles can be efficiently prepared in moderate to good yields from 2-(1-alkynyl)benzenamines and disulfides using the palladium/air catalytic systems. The study also provides a useful route to the synthesis of fipronil analogues.
A novel and efficient palladium-catalyzed three-component cascade cyclization/arylthiolation has been developed for the assembly of diverse 3-sulfenylindole and 3-sulfenylbenzofuran derivatives from 2-alkynylamines and 2-alkynylphenols, aryldiazonium salts, and Na2S2O3 under aerobic conditions with PEG-200 as an environmentally benign medium. The current study features exceptional functional group
Microwave assisted metal-/oxidant-free cascade electrophilic sulfenylation/5-endo-dig cyclization of 2-alkynylanilines to generate diversified 3-sulfenylindoles
作者:Shivani Sharma、Ramdas S. Pathare、Sukanya、Antim K. Maurya、Bhagyashree Goswami、Vijai K. Agnihotri、Devesh M. Sawant、Ram T. Pardasani
DOI:10.1016/j.tetlet.2017.08.046
日期:2017.10
A metal-/oxidant-free sustainable protocol for the synthesis of 3-sulfenylindoles based on electrophilic cyclization of 2-alkynylanilines has been developed under microwave irradiation. Herein, catalytic amount of iodine and stoichiometric amount of sulfonyl hydrazides were employed as catalyst and electrophiles respectively to induce the 5-endo-dig cyclization of 2-alkynylanilines. This strategy allows a wide substrate scope, demonstrates good functional group tolerance, utilizes easily available reagents and overcome multistep synthesis. (C) 2017 Elsevier Ltd. All rights reserved.