A novel protocol for the stereoselective synthesis of variously substituted (Z)-5-ylidene-5H-furan-2-ones
摘要:
The Pd(II)- or Ag(I)-catalyzed lactonization of easily available (E)-4-(1-alkynyl)-2-bromopropenoic acids provides (Z)-3-bromo-5-ylidene-5H-furan-2-ones, 9. These compounds, which represent an unpreviously reported class of (Z)-alkylidenebutenolides, are able to undergo Pd-catalyzed cross-coupling reactions with arylzinc halides, tetraalkylstannanes or alkenylstannanes to provide the corresponding 3-substituted (Z)-5-ylideng-5H-furan-2-ones, 1. The new procedure for the preparation of compounds 1 has been employed in a new synthesis of the butter flavour component bovolide. (C) 1998 Elsevier science Ltd. All rights reserved.
Reported herein is a palladium-catalyzed secondary benzylic imidoylative Negishi reaction leveraging the sterically bulky aromatic isocyanides as the imine source. This method allows the facile access of alkyl-, (hetero)aryl-, and alkynylzinc reagents to afford various α-substituted phenylacetone products under mild acidic hydrolysis, which are ubiquitous motifs in many pharmaceuticals and biologically
The Negishicoupling of aryl bromides or acyl chlorides with organozinc chlorides catalyzed by a palladiumbipyridylcomplex anchored on nanosized mobile crystalline material 41 (MCM‐41) were investigated. The reactions proceeded smoothly with a very low catalyst loading in THF at 70 °C for electron‐deficient aryl bromides, which gave good to high yields of the Negishicoupling products. However, reactions
Multicomponent Assembly Strategies for the Synthesis of Diverse Tetrahydroisoquinoline Scaffolds
作者:Brett A. Granger、Kyosuke Kaneda、Stephen F. Martin
DOI:10.1021/ol201739u
日期:2011.9.2
the rapid and efficient assembly of various heterocyclic scaffolds bearing a tetrahydroisoquinoline core, each of which allows for facile derivatization to access a diverse array of compounds. This work led to the serendipitous discovery of a new method for the synthesis of a fused quinazolone ringsystem, which was applied to a one-step total synthesis of the quinazolinocarboline alkaloid rutaecarpine
Synthesis of polyphenylene derivatives by thermolysis of enediynes and dialkynylaromatic monomers
作者:Jens A John、James M Tour
DOI:10.1016/s0040-4020(97)00977-0
日期:1997.11
Described are the syntheses of substituted enediynes and dialkynylaromatics using Pd- or cross coupling procedures. The products were then thermalized to afford the corresponding poly(p-phenylene)s, poly(1,4-naphthalene)s, poly(benzo[c]thiophene)s, and poly(dibenzothiophene)s. Fifteen examples are provided that show the scope of the polymerization process based upon substituent patterns and cyclization
Highly selective mono-substitution in Pd-catalyzed cross-coupling reactions of 3,6-dichloropyridazine with organozinc compounds
作者:Dmitriy S. Chekmarev、Alexander E. Stepanov、Alexander N. Kasatkin
DOI:10.1016/j.tetlet.2004.12.124
日期:2005.2
Pd-catalyzedcross-couplingreactions of 3,6-dichloropyridazine (1) with benzyl, aryl, and alkyl organozinc compounds led to selective mono-substitution of one of the chlorine atoms. The subsequent cross-coupling of the resulting monochlorides with RZnCl afforded unsymmetrical 3,6-carbon-disubstituted pyridazines.