21160-29-2Relevant articles and documents
Copper(II)-Catalyzed [4+1] annulation of propargylamines with N,O-acetals: Entry to the synthesis of polysubstituted pyrrole derivatives
Sakai, Norio,Hori, Hiroaki,Ogiwara, Yohei
, p. 1905 - 1909 (2015/03/18)
Described herein is the CuCl2-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 sp3-carbon is required, the central sp3-carbon displays the functions of both an electrophile and a nucleophile, and liberation of the secondary amine smoothly leads to the aromatization. A CuCl2-catalyzed [4+1] annulation of propargylamines with N,O-acetals having an ester, a ketone, and an amide moiety, leading to the facile preparation of polysubstituted pyrrole derivatives is presented. This annulation series was achieved through 5-endo-dig cyclization and subsequent aromatization in one pot.
