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Copper(II)‐Catalyzed [4+1] Annulation of Propargylamines with N , O ‐Acetals: Entry to the Synthesis of Polysubstituted Pyrrole Derivatives
Author(s) -
Sakai Norio,
Hori Hiroaki,
Ogiwara Yohei
Publication year - 2015
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201500098
Subject(s) - annulation , chemistry , aromatization , nucleophile , electrophile , pyrrole , acetal , substituent , amine gas treating , catalysis , medicinal chemistry , organic chemistry , stereochemistry
Described herein is the CuCl 2 ‐catalyzed [4+1] annulation of a variety of propargylamines with N , O ‐acetals that function as a C1 unit, leading to the production of polysubstituted pyrrole derivatives. Three important features of the N , O ‐acetal during the [4+1] annulation series via 5‐endo‐dig cyclization are described: an enolizable substituent adjacent to the central sp 3 ‐carbon is required, the central sp 3 ‐carbon displays the functions of both an electrophile and a nucleophile, and liberation of the secondary amine smoothly leads to the aromatization.