Emmert还原缩合反应

在铝或镁汞齐存在下醛酮与吡啶或其衍生物缩合生成吡啶基烷基或二烷基甲醇的反应。反应通常会有异构体产生，吡啶的2,4位都可以反应。此反应只有铝和镁两种金属反应效果好。底物除了醛酮，N,N-二烷基酰胺或腈也能反应，但产率较低。

反应机理

反应实例

1-(2-Pyridyl)- and 1-(4-pyridyl)cyclohexanol (3a, 3b). A mixture of HgCl2 (1.0 g, 3.7 mmol) and Al turnings (15.0 g, 0.55 mol) was heated for 15 min at 120 C. Pyr 1 (19.0 g, 0.24 mol) and 2 (17.7 g, 0.18 mmol) were added with vigorous stirring. When the reaction commenced, 1 (75.8 g, 0.96 mol) was added at once and 2 (60.8 g, 0.82 mol) was added at a rate that kept the mixture refluxing (1.5 h). The cooled mixture (2 h) was poured into 100 mL well stirred 6N NaOH. The aq layer was extracted with PhH and the PhH solution was extracted with 6N HCl. The HCl solution was basified with NaOH pellets and after distillation afforded a crude mixture of 3a and 3b (50 g). Recrystallization gave 45.7 g of 3a þ 3b (29%), mp 42–43 C.

【Lochte HL, J Am Chem Soc., 1953, 75, 4477】

相关文献

1 Emmert B Chem Ber 1939 72b 1188

2 Tilford CH J Am Chem Soc 1948 70 4001

3 Lochte HL J Am Chem Soc 1953 75 4477

4 Russel CA J Chem Soc 1970 1406

5 Tripathi AK ARKIVOC 2009 xii 241

编译自：Organic Syntheses Based On Name Reactions, 3RdEd, A. Hassner, Page 138.

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