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Iron(III) Chloride/Diorganyl Diselenides Promoted Regio‐ and Stereoselective Cyclization of ortho ‐Alkynylanilides: Synthesis of ( Z )‐4‐(chalcogen)methylenebenzoxazines
Author(s) -
Stein André L.,
Bilheri Filipe N.,
Back Davi F.,
Zeni Gilson
Publication year - 2014
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201300925
Subject(s) - chemistry , stereoselectivity , chalcogen , iron(iii) chloride , dichloromethane , solvent , reagent , chloride , organic chemistry , ammonium acetate , intramolecular force , medicinal chemistry , ammonium chloride , catalysis , high performance liquid chromatography
Intramolecular 6‐ exo‐dig cyclization of ortho ‐alkynylanilides has been employed in a regio‐ and stereoselective synthesis of ( Z )‐4‐(chalcogen)methylenebenzoxazines. Several reaction parameters were screened for the efficient cyclization of ortho ‐alkynylanilides. Among them, the reaction of ortho ‐alkynylanilides (0.25 mmol) with iron(III) chloride (3.0 equiv.) and diorganyl diselenides (0.75 equiv.) in dichloromethane as solvent gave the products in acceptable to good yields. The resulting products were then subjected to a nitrogen–oxygen exchange reaction with ammonium acetate to furnish quinazoline derivatives. The one‐pot version of this cyclization, starting directly from 2‐alkynylanilines, avoiding the previous preparation of ortho ‐alkynylanilides was also briefly studied.