Achmatowicz反应

糠醇类化合物在Br2、NBS、mCPBA、TBHP-VO(acac)2等氧化条件下重排合成二氢吡喃环的反应。在甲醇中进行电化学氧化也能进行此反应。产物吡喃糖是呋喃环的1,4-二酮等价体。1971年波兰的化学家Achmatowicz Jr.等人利用液溴作为氧化剂氧化糠醇首次成功合成了呋喃糖类化合物。所以该反应以及类似反应他名字被命名。

该产物与原甲酸甲酯和三氟化硼反应上甲基保护基，接着用硼氢化钠还原酮基，可得另一吡喃衍生物，这个产物可用作许多单糖的合成中间体。

反应机理

糠醇与溴在甲醇中反应，先得到2,5-二甲氧基-二氢糠醇，它用稀硫酸发生重排便得到二氢吡喃衍生物。

反应实例

【 Org. Lett. 2006, 8, 1609】

Freshly distilled acetyl chloride (5.64 g,72.4 mmol) was added to a solution of 5 (7.96 g, 72.4 mmol) in CH3CN (20 mL) followed by ammoniumceric nitrate (1.94 g, 3.56 mmol) in CH3CN (20 mL). After usual workup and flash chromatography oversilica gel (n-hexane/EA 3:1), product 6 was isolated as a yellow oil. To a solution of 6 (0.954 g,6.624 mmol) in PhCH3 (20 mL) was added BH3SMe2 (2M in THF, 0.504 g, 6.624 mmol) in PhCH3(10 mL), the mixture was stirred for 3 h at r.t. and then quenched with sat NH4Cl solution. Afterusual workup and flash chromatography over silica gel (n-hexane/EA 3:1), pure 7 was isolated asa pale yellow oil. Compound 7 (0.292 g, 2 mmol) was added to a solution of m-CPBA (0.344 g, 2 mmol)in CH2Cl2 (2 mL) at 0 C and the mixture was stirred for 3 h till a ppt was formed. The precipitatedm-chlorobenzoic acid was filtered and the filtrate was concentrated in vacuo to afford the crude productwhich was purified by flash chromatography over silica gel (n-hexane/EA 3:1) to afford 8 as a colorlessliquid, 70%.

【 Zuhal G, Turk J Chem. 2007, 31, 491】

Furfuryl alcohol 1 (4.90 g, 50.0 mmol, 1.0 equiv) was dissolved in 100 mL of drydichloromethane and cooled to 0 oC. To this solution was added 77% m-CPBA (12.3 g,55.0 mmol, 1.1 equiv) in two equal portions with 15 minutes in between. The reactionwas stirred for an additional 60 minutes and TLC revealed that nearly completeconsumption of starting material had occurred. The solid byproducts were filtered off byvacuum filtration (Note: do not wash this solid with additional CH2Cl2). The filtrate wasplaced in the refrigerator overnight and the additional solid that formed was filtered offby vacuum filtration (Note: do not wash this solid with additional CH2Cl2). While thissolution of crude product was taken on directly, an analytical sample can be obtained byflash chromatography using 33% EtOAc in hexanes to give the pure product 2 as ayellow oil (Rf = 0.15, 33% EtOAc in hexanes) which solidifies at low temperature.Spectroscopic information was in agreement with published data.

【J. Org. Chem. 2008, 73, 3, 882-888】

【 J. Org. Chem. 2008, 73, 5, 1935-1940】

【J. Am. Chem. Soc. 2010, 132, 19, 6855-6861】

相关文献

1 Achmatowicz O, Tetrahedron, 1971, 27, 1973

2 Shono T, Chem Lett. 1981, 1121

3 Georgiadis MP, J Org Chem. 1986, 51, 2725

4 Zhou W-S, J Chem Soc Chem Comm. 1997, 317

5 O’Doherty GA, Tet Lett. 2000, 41, 183

6 Schreiber SL, Angew Chem Int. 2004, 43, 57

7 Schreiber SL, J Am Chem Soc. 2004, 126, 14096

8 Zuhal G, Turk J Chem. 2007, 31, 491

9 Boger DL, J Am Chem Soc. 2010, 132, 2157

10 Nicolaou KC., J Am Chem Soc., 2010, 132, 6855, 8219

参考文献

一、Organic Syntheses Based On Name Reactions, 3RdEd, A. Hassner, Page 3.

二、“化学空间”：http://www.chem-station.com/cn/?p=3779