Burgess试剂

Burgess试剂，即N-(三乙基铵磺酰)氨基甲酸甲酯，是一个氨基甲酸酯类的内盐，用作有机化学中的脱水剂。它可溶于大多数有机溶剂中，CAS号为51373-37-6。Burgess脱水试剂是非常有效的由仲醇和叔醇脱水制备烯烃的试剂，反应温和，有选择性。但一级醇反应效果不佳。β位消除，遵循热消除Ei机理（消除过程中，两种离去基团同时离去，互相之间又迅速成键）。

试剂的制备：

(a) Burgess, E. M.; Penton, H. R., Jr.; Taylor, E. A.; Williams, W. M. Org. Synth. Coll. Edn. 1987, 6, 788–791. (b) Duncan, J. A.; Hendricks, R. T.; Kwong, K. S. J. Am.Chem. Soc. 1990, 112, 8433–8442.

反应机理

先和醇反应生成磺酸酯，接着β位消除，遵循热消除Ei机理。

Khapli, S.; Dey, S.; Mal, D. J. Indian Inst. Sci. 2001, 81, 461–476. (Review).

反应实例

对于伯醇一般是更容易发生取代反应，而不是消除脱水。

【Wipf, P.; Xu, W. J. Org. Chem. 1996, 61, 6556–6562.】

该试剂不仅能用于烯的合成，也能用于腈，异腈以及氧化腈的合成。此外它还被用于合成杂环恶唑啉和噻唑啉。

【Wipf, P.; Fritch, P. C. Tetrahedron Lett. 1994, 35, 5397】

To a flamedried reaction vessel equipped witha stir bar and septum was added 4-(4-nitrophenyl)butan-1-ol (0.21 mL, 1.25mmol) followed by a benzene solution of 1 (5.0 mL, 1.25 mmol, 0.25 M).The septum was then removed and quickly replaced with a Teflon cap prior to thereaction being placed into a 50°C bath. After 1 h, the bath temperature wasincreased to 85°C and a small aliquot of the reaction mixture was removed tocheck for the formation of the initial adduct 2 (LC/MSgenerally shows M++18(H2O): 426). The reaction was stirred for 12–16 h and thenperiodically monitored, by LC/MS, for the disappearance of 2.(CAUTION: Remove the reaction vessel from the heating bath and allow itstemperature to drop below the boiling point of the solvent prior to removing ananalytical sample.) Frequently, LC/MS spectra obtained prior towork-up show numerous side products that disappear after work-up. Aftercomplete disappearance of 2, the reaction was cooled to ambienttemperature, benzene was removed in vacuo, and the residue was partitionedbetween EtOAc and 0.5 M HCl. The organic layer was washed with 5% sodiumbicarbonate and brine, then dried over sodium sulfate. Filtration, solventremoval and silica gel chromatography (10–60% EtOAc in hexanes, lineargradient) provided the target compound (318 mg, 77%) as a white solid.

【Tetrahedron Letters 2002, 3887–3890】

Fredericamycin的合成【Kita, Y. et al. J. Am. Chem. Soc. 2001,123, 3214.】

Taxol的合成【Holton, R. A. et al. J. Am. Chem. Soc. 1994, 116, 1597. 】

Penitrem D的合成【Smith, A. B., III et al. J. Am. Chem. Soc. 2003, 125, 8228.】

【Miller, C. P.; Kaufman, D. H. Synlett 2000, 8, 1169–1171.】

Keller, L.; Dumas, F.; D’Angelo, J. Eur. J. Org. Chem. 2003, 2488–2497.

【Nicolaou, K. C.; Snyder, S. A.; Longbottom, D. A.; Nalbandian, A. Z.; Huang, X. Chem. Eur. J. 2004, 10, 5581–5606.】

参考文献

一、Name Reactions （A Collection of Detailed Reaction Mechanisms）, Jie Jack Li, Burgess dehydrating reagent，page 95-96.

二、化学空间：http://www.chem-station.com/cn/reactions/%e6%b6%88%e9%99%a4%e5%8f%8d%e5%ba%94/2014/08/post-2566.html