重氮化合物是有机定制合成中非常重要的一类中间体,一般指脂肪族重氮化合物,大多具爆炸性。重氮化合物中的重氮基有四个共振式,中间氮原子带有部分正电荷,两端的碳和氮原子带负电荷。α-重氮酮和α-重氮酯中的负电荷可以离域到羰基上去,因此比较稳定。
肟与次氯酸钠和氨水作用得到重氮化合物的反应被称为Forster反应。此反应由Forster在1915年首先报道,他利用α-肟基酮和氯胺反应得到了重氮酮。
反应机理
反应实例
2-Diazo-4,4-dimethylcholest-5-en-3-one (5). 4N aq NaOH (125 mL) and 40 mL conc NH4OH were added to 10 g of 2-oximino-4,4-dimethylcholest-5-en-3-one (4, 10 g) in a minimum amount of THF, followed by slow addition of 100 mL of aq 5.25% NaOCl (Clorox) at 10 C over 1 h with vigorous stirring. Addition of water produced 8.7 g of a yellow solid. Chromatography (alumina, CHCl3, MeOH) and air drying afforded 6.74 g of 5, mp 129–130 C. Additional 0.97 g fromthe filtrate, total yield of 5 was 78%.
相关文献
1 Forster MCJ J Chem Soc 1915 107 260
2 Meinwald J J Am Chem Soc 1959 81 4751
3 Kirmse M Angew Chem 1957 69 106
4 Rundel W Angew Chem 1962 74 469
5 Hassner A Tet Lett 1962 3 759
6 Cava MP Steroids 1964 4 1789
7 Brewer M Org Lett 2007 9 1789
8 Davies HML Org Lett 2007 9 2625
编译自:Organic Syntheses Based On Name Reactions, 3RdEd, A. Hassner, Page 161.