赛费特-吉尔伯特增碳反应
(重定向自Seyferth–Gilbert增碳反应)
赛费特-吉尔伯特增碳反应(Seyferth-Gilbert homologation),又称赛费特-吉尔伯特同系化反应,指芳酮(或醛)与重氮甲基膦酸二甲酯(赛费特-吉尔伯特试剂)在叔丁醇钾存在下反应生成取代炔烃。[1][2][3]
![赛费特-吉尔伯特同系化](http://images.weserv.nl/?url=//upload.wikimedia.org/wikipedia/commons/thumb/e/e0/Seyferth-Gilbert_Homologation_Scheme.png/320px-Seyferth-Gilbert_Homologation_Scheme.png)
重氮甲基膦酸二甲酯是此反应中的一碳试剂。产物是比原料羰基化合物多一个碳的炔类,故名增碳反应或同系化反应。
反应机理
赛费特-吉尔伯特试剂被碱去质子化,生成碳负离子,并对酮羰基进行亲核加成,生成的烷氧基负离子再分子内进攻磷原子,环化生成噁磷杂丁环,然后开环,放出磷酸二甲酯,并产生乙烯基重氮化合物(Fa Fb),后者最后放出氮气,得乙烯基卡宾,并发生1,2-迁移,得最终产物芳炔。
![赛费特-吉尔伯特增碳反应的机理](http://images.weserv.nl/?url=//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Seyferth-Gilbert_Homologation_Mechanism.png/650px-Seyferth-Gilbert_Homologation_Mechanism.png)
贝斯特曼改进法
通过1-重氮基-2-氧代丙基膦酸二甲酯(贝斯特曼试剂)与甲醇和碳酸钾反应,在反应体系中原位产生赛费特-吉尔伯特试剂。
![贝斯特曼试剂](http://images.weserv.nl/?url=//upload.wikimedia.org/wikipedia/commons/thumb/a/a3/Bestmann%27s_Reagent_Scheme.png/300px-Bestmann%27s_Reagent_Scheme.png)
参见
参考资料
- ^ D. Seyferth, R. S. Marmor and P. Hilbert. Reactions of dimethylphosphono-substituted diazoalkanes. (MeO)2P(O)CR transfer to olefins and 1,3-dipolar additions of (MeO)2P(O)C(N2)R. J. Org. Chem. 1971, 36 (10): 1379–1386. doi:10.1021/jo00809a014.
- ^ J. C. Gilbert and U. Weerasooriya. Diazoethenes: their attempted synthesis from aldehydes and aromatic ketones by way of the Horner-Emmons modification of the Wittig reaction. A facile synthesis of alkynes. J. Org. Chem. 1982, 47 (10): 1837–1845. doi:10.1021/jo00349a007.
- ^ D. G. Brown, E. J. Velthuisen, J. R. Commerford, R. G. Brisbois and T. H. Hoye. A Convenient Synthesis of Dimethyl (Diazomethyl)phosphonate (Seyferth/Gilbert Reagent). J. Org. Chem. 1996, 61 (7): 2540–2541. doi:10.1021/jo951944n.
- ^ S. Müller, B. Liepold, G. Roth and H. J. Bestmann*. An Improved One-pot Procedure for the Synthesis of Alkynes from Aldehydes. Synlett. 1996, 1996 (06): 521–522. doi:10.1055/s-1996-5474.
- ^ G. Roth, B. Liepold, S. Müller and H. J. Bestmann. Further Improvements of the Synthesis of Alkynes from Aldehydes. Synthesis. 2004, 2004 (1): 59–62. doi:10.1055/s-2003-44346.
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