A Method to Access Symmetrical Tetrasubstituted Pyridines via Iodine and Ammonium Persulfate Mediated [2+2+1+1]-Cycloaddition Reaction
作者:Weibing Liu、Hua Tan、Cui Chen、Yupeng Pan
DOI:10.1002/adsc.201601225
日期:2017.5.2
productive preparation of symmetrical 2,3,5,6‐tetrasubstituted pyridines has been developed from α‐substituted arones and N,N‐dimethyl formamide (DMF) using iodine (I2) and ammonium persulfate ((NH4)2S2O8) as mediators. In this process, both DMF and (NH4)2S2O8 play a dual role for the formation of pyridines. DMF acts as the reaction medium and the C4 source (the methyl group of DMF), while (NH4)2S2O8 serves
由α-取代的芳烃和N,N-二甲基甲酰胺开发了一种新颖的无金属[2 + 2 + 1 + 1]-环加成方法,用于快速,高效地制备对称的2,3,5,6-四取代吡啶(使用碘(I 2)和过硫酸铵((NH 4)2 S 2 O 8)作为介体。在这个过程中,DMF和(NH 4)2 S 2 O 8都对吡啶的形成起双重作用。DMF用作反应介质和C4源(DMF的甲基),而(NH 4)2 S 2 O 8用作氧化剂和氮源。值得注意的是,该转化对多种不同的芳族化合物显示出较宽的底物范围,从而以中等至优异的产率得到相应的四取代的吡啶。
Palladium-Mediated Tandem Isomerization–Methylenation of Allyl Alcohols: One-Pot Synthesis of 1,5-Diketones
A novel methodology for the synthesis of 1,5-diketones through a one-pot isomerization–methylenation of a variety of allylicalcohols has been established for the first time. This methodology utilizes commercially available palladium acetate and easily accessible BINOL phosphoric acid. Both isomerization of allylicalcohol and oxidation of methanol occurred through a single catalyst. The practical
首次建立了一种通过多种烯丙醇的单锅异构化-亚甲基化合成 1,5-二酮的新方法。该方法使用市售的醋酸钯和易于获取的 BINOL 磷酸。烯丙醇的异构化和甲醇的氧化都是通过单一催化剂发生的。该方法的实际效用已通过连续加成合成取代的吡啶来证明。机理研究表明,烯丙醇异构化为相应的酮,最终进行甲基化,生成 1,5-二酮,其中 H 2和 H 2 O 作为唯一的副产物。
Simple Selective Synthesis of 2,4- and 2,6-Diarylpyridines through Metal-Free Cyclocondensation of Aromatic Ketones with Ammonium Acetate
A simple and selective one-pot synthesis of 2,4- and 2,6-diarylpyridines through the cyclocondensation reaction of aromatic ketones with ammonium acetate has been developed. The procedure is metal-free, convenient, and efficient, and the substrates are readily available.