Sonogashira/N-acyliminium ion aromatic π-cyclisation processes: access to tetra- and pentacyclic lactams
作者:Ronald Grigg、Visuvanathar Sridharan、David A. Sykes
DOI:10.1016/j.tet.2008.06.044
日期:2008.9
Application of the Sonogashira reaction of N-alkynylimides with 2-iodophenol or 2-iodo-N-tosylaniline affords 2-(N-alkylimino)-benzofurans and indoles in good yield. Selective partial reduction of the latter followed by treatment with TsOH generates N-acyliminium ions, which cyclise to afford tetra- and pentacyclic lactams in good yield. The latter are reduced to the analogous cyclic amines by BH3. (C) 2008 Elsevier Ltd. All rights reserved.