Brandi-Guama螺环丙烷重排反应

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腈氧化物或硝酮对甲叉基环丙烷进行[3+2]-偶极环加成得到异恶唑烷-5-螺环丙烷,接着加热或光照重排生成4-吡啶酮衍生物的反应。腈氧化物作为底物则生成不饱和吡啶酮衍生物,硝酮则生成4-哌啶酮。


腈氧化物可以由硝基烷烃制备得到直接用于反应。


反应机理

反应实例

Spiro 4,5-dihydro-3-methylisoxazole-5,10-20-phenylcyclopropane (3). Nitroethane (1.3 g, 22 mmol) and Et3N (262 mg, 2.6 mmol) in PhH (11 mL) was added over 1 h to a refluxing solution of 1-methylene 2-phenylcyclopropane 2 (1.88 g, 14.5 mmol) and phenyl isocyanate (1.24 g, 23 mmol) in PhH (10 mL)

under stirring. After 18 h stirring at 20 C, the mixture was filtered and vacuum distilled to give recovered 1 (45–65 C, 0.5 torr). The residue was chromatographed (DCM) to give 1g of 3 (40%), mp 85 C.

2-Methyl-6-phenyl-dihydropyrid-4-one (4). Vapours of 3 (260 mg, 1.4 mmol) were passed at 0.04 torr through a quartz tube heated at 400 C then led into a cold trap. Washing with PE afforded 216 mg of 4 (83%), mp 162 C (CHCl3 – PE).

【 Brandi A, Guama A, J Org Chem, 1988, 53, 2426, 2430】




相关文献

1 Brandi A, Guarna A J Chem Soc Chem Comm 1985 1518

2 Brandi A, Guarna A Tet Lett 1986 27 1727

3 Brandi A, Guama A J Org Chem 1988 53 2426, 2430

4 Brandi A J Org Chem 1992 57 5666

5 Brandi A Tetrahedron 1993 49 9867

6 Brandi A, Guarna A Synlett 1993 1

7 Brandi A Tet Lett 1995 36 1343

8 Brandi A J Org Chem 1995 60 4743, 6806

9 Brandi A, de Meijere A J Org Chem 1996 61 1665

10 Brandi A, de Meijere A Eur J Org chem 2006 5485

11 Brandi A, de Meijere A Synlett 2010 1939



编译自:Organic Syntheses Based On Name Reactions, 3RdEd, A. Hassner, Page 60.




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