1,3-Dipolar cycloaddition of azomethine ylides derived from imines and difluorocarbene to alkynes: a new active Pb-mediated approach to 2-fluoropyrrole derivatives
作者:Mikhail S. Novikov、Alexander F. Khlebnikov、Elena S. Sidorina、Rafael R. Kostikov
DOI:10.1039/a905518e
日期:——
Domino reactions of imines with difluorocarbene in the presence of electron-deficient alkynes lead to 2-fluoropyrrole derivatives. The process involves intermediate azomethine ylide formation, its 1,3-dipolar cycloaddition to alkyne, followed by dehydrofluorination. A modified difluorocarbene generation method using active lead for dibromodifluoromethane reduction is proposed, providing shorter reaction
The cyclometallation of anthracen-9-ylmethylene-phenyl-amine with palladium(II) acetate and with the system PdCl2, NaCl and NaOAc . 3H(2)O is studied. In both cases, the Cl-H bond activation of the anthracen-9-yl group takes place, affording an entry to a new type of endocyclic six-membered cyclopalladated organic imine that contains a metallated aromatic carbon atom. (C) 2000 Elsevier Science S.A. All rights reserved.