Iron(III) Chloride/Diorganyl Diselenides Promoted Regio- and Stereoselective Cyclization of<i>ortho</i>-Alkynylanilides: Synthesis of (<i>Z</i>)-4-(chalcogen)methylenebenzoxazines
作者:André L. Stein、Filipe N. Bilheri、Davi F. Back、Gilson Zeni
DOI:10.1002/adsc.201300925
日期:2014.2.10
AbstractIntramolecular 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.magnified image
Synthesis of 2-phenylindole N-derivatives under conditions of catalysis by palladium complexes