Brown炔基异构化反应

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1,3-丙二胺基钾作用下,非端基炔通过丙二烯中间体异构化为端基炔的反应。整个异构化的过程,炔基像拉链一样,从链中异构化到链端,因此此反应也被称为炔基拉链反应。此反应最早由Charles Allen Brown和Ayako Yamashita在1975年首先报道【 J. Am. Chem. Soc. 97 (4): 891–892】。此反应常见的底物是长链的炔醇,碱最开始是将KH加入到1,3-丙二胺溶剂中得到直接用于反应。由于KH比较危险,后来也发展出了替代方法:利用1,3-丙二胺的锂盐和叔丁醇钾进行反应。


反应机理


反应实例

16-Heptadecyn-1-ol (2). A mixture of potassium (190 mg, 4.8 mmol) in 1,3-propanediamine (5 mL) with ferric nitrate (1 mg) was heated to 90 C in an ultrasound cleaning bath. After 10–15 min, potassium disappeared and a green–brown solution of KAPA was formed which was cooled to 0 C and

12-heptadecyn-1-ol (1, 190 mg, 0.75 mmol) in THF (1 mL) was added. After 30 min stirring at 0 C, the mixture was poured into H2O (125 mL) and extracted with hexane (3  100 mL). The extract was dried (MgSO4) and evaporated to yield 185 mg of 16-heptadecyn-1-ol (2, 98%), mp 41 C.

【Becker D, J Org Chem., 1984, 49, 2494】



23-Tetracosyn-1-ol (4). 1,3-Diaminopropane (10 mL) under N2 was treated with Li (140 mg, 20 mmol) under heating (70 C) and stirring. After 2 h, the mixture was cooled to 20 C, KOt-Bu (1.3 g, 12 mmol) was added and stirring was continued for another 15 min when 7-tetracosyn-1-ol (3, 1.05 g, 3 mmol) was added. After 2 h stirring the mixture was quenched with water and usual workup gave after chromatography (silica gel, hexane:Et2O 1:1) 860 mg of 4 (82%), mp 76 C.

【Abrams SR, Can J Chem., 1984, 62, 1333】


相关文献

1 Brown CA J Am Chem Soc 1975 97 891

2 Brown CA J Chem Soc Chem Commun 1976 959

3 Macaulay SR J Org Chem 1980 45 734

4 Becker D J Org Chem 1984 49 2494

5 Abrams SR Can J Chem 1984 62 1333

6 Shaw AC Org Synth Coll Vol 1988 8 146

7 Balova IA Russ J Org Chem 2003 39 1613

8 Balova IA Eu J Org Chem 2005 882



编译自:Organic Syntheses Based On Name Reactions, 3RdEd, A. Hassner, Page 63-64.


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