Cyclisation of acetylenic ethoxylactams 1b-12b leads to bridgehead nitrogen bicyclic ketones in excellent yields. The reaction is weakly acid-catalysed and proceeds at ambient temperature. The observed regioselectivity effect is discussed in terms of stability of exo vs endo vinylcations and ring strain effects. The high yield conversion of N-(5-hexynyl)-ethoxy lactams 7b and 8b in the 5/8 and 6/8
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.
SCHOEMAKER H. E.; BOER-TERPSTRA T.; DIJKINK J.; SPECKAMP W. N., TETRAHEDRON, 1980, 36, NO 1, 143-148
作者:SCHOEMAKER H. E.、 BOER-TERPSTRA T.、 DIJKINK J.、 SPECKAMP W. N.
DOI:——
日期:——
Gesson, J. P.; Jacquesy, J. C.; Rambaud, D., Bulletin de la Societe Chimique de France, 1992, # 3, p. 227 - 231
作者:Gesson, J. P.、Jacquesy, J. C.、Rambaud, D.
DOI:——
日期:——
Cousson, Alain; Gazeau, Catherine; Gesson, Jean-Pierre, Bulletin de la Societe Chimique de France, 1994, vol. 131, # 1, p. 95 - 104