Superacid catalyzed ring-opening reactions involving 2-oxazolines and the role of superelectrophilic intermediates
摘要:
A variety of 2-oxazolines are found to react with arenes in superacidic triflic acid, CF3SO3H. It is proposed that the 2-oxazolines are protonated twice in triflic acid and the resulting intermediates undergo ring-opening reactions to produce reactive, dicationic species. These superelectrophiles are capable of reacting with benzene and o-dichlorobenzene in high yields by Friedel-Crafts type reactions. (C) 2004 Elsevier Ltd. All rights reserved.
Regioselective cycloadditions of N-protonated azomethine ylides and 2-azaallyl anions generated from N-(silylmethyl) thioimidates, synthetic equivalents of nonstabilized nitrile ylides
N-PROTONATED AZOMETHINE YLIDES WITH A LEAVING GROUP AS SYNTHETIC EQUIVALENTS FOR NONSTABILIZED NITRILE YLIDES
作者:Otohiko Tsuge、Shuji Kanemasa、Koyo Matsuda
DOI:10.1246/cl.1985.1411
日期:1985.9.5
steps, N-(silylmethyl)amidines generate N-protonated azomethine ylides which cycloadd to olefins, acetylenes, and aldehydes giving 1- or 2-pyrrolines, pyrroles, and 2-oxazolines, respectively, after the elimination of N-substituted anilines. With this sequence, the amidines are useful synthetic equivalents of nonstabilized nitrileylides.
An efficient catalytic protocol based on reusable MgAl-layered double hydroxides has been developed for the synthesis of multi-functionalized oxazolines via the cyclocondensation of amidines and aminoalcohols. The developed method has a broad substrate scope and excellent functionalgroup tolerance and uses a reusable catalyst. The catalyst can be conveniently recycled by filtration and reused for
A new general route to N-protonated azomethine ylides from N-(silylmethyl)amidines and -thioamides. Cycloaddition of synthetic equivalents of nitrile ylides
作者:Otohiko Tsuge、Shuji Kanemasa、Koyo Matsuda
DOI:10.1021/jo00361a012
日期:1986.5
TSUGE, OTOHIKO;KANEMASA, SHUJI;MATSUDA, KOYO, CHEM. LETT., 1985, N 9, 1411-1414
作者:TSUGE, OTOHIKO、KANEMASA, SHUJI、MATSUDA, KOYO
DOI:——
日期:——
TSUGE OTOHIKO; KANEMASA SHUJI; MATSUDA KOYO, J. ORG. CHEM., 51,(1986) N 11, 1997-2004