A Reliable Multikilogram-Scale Synthesis of 2-Acetamido-5-Vinylpyridine Using Catalytic BINAP in a Modified Heck Reaction

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• 作者：Jeffrey W. Raggon and William M. Snyder
• 刊名：Organic Process Research & Development
• 出版年：2002
• 出版时间：January 2002
• 年：2002
• 卷：6
• 期：1
• 页码：67 - 69
• 全文大小：34K
• 年卷期：v.6,no.1(January 2002)
• ISSN：1520-586X

文摘

An optimized Heck ethylenation of 2-acetamido-5-bromopyridine using a unique catalytic combination of phosphine ligands,tri-o-tolylphosphine and BINAP (S-(-)- or racemic) as anadditive/promoter is described. The best conditions for ethylenation were determined to be 1 mol % of palladium acetate,3.3 mol % of tri-o-tolylphosphine, 0.25 mol % of BINAP and180 mol % of triethylamine in acetonitrile at 90 C. Inoptimizing the reaction, the purity of the tri-o-tolylphosphinewas critical. The reaction time was extended by 3-fold whenlower purity phosphine was used. The final process was carriedout on 46.5 mol of 2-acetamido-5-bromopyridine, providing71.6% of the corresponding vinyl-substituted pyridine adduct.