Eschenmoser脱硫反应

硫代酰胺或硫代羧酸和α-卤代酮反应后，通过环硫化合中间体脱硫生成烯胺酮或β-羰基酮的反应。生成的环硫中间体是通过和亲硫的三芳基膦或三烷基膦反应脱硫的。

反应机理

反应操作

Thioester (6). To a solution of thiobutyric acid 5 (3.16 g, 30 mmol) and Et3N (4.20 mL) in Et2O was added 1-bromobutan-2-one (3.06 mL, 30 mmol). After 2 h reflux, the mixture was filtered through Celite, the solvent evaporated and the residue distilled (Kugelrohr, 110℃/0.3 Torr) to afford 4.925 g of 6 (95%).

3,5-Octandione (7). To a solution of 6 (442 mg, 2.54 mmol) and anhyd LiBr (259 mg, 2.83 mmol) in MeCN was added bis(3-dimethylaminopropyl) phenylphosphine (2.2 mL). The reaction mixture was heated under N2 for 17 h at 70 ℃. The cooled mixture (0 ℃) was quenched with ice water (10 mL) and

conc HCl (1.3 mL). Extraction with Et2O:DCM (5:1), evaporation of the solvent and distillation (Kugelrohr, 90–105 ℃/10 Torr) afforded 336 mg of 7 (93%).

【Eschenmoser A, Helv Chim Acta., 1971, 54, 710】

相关文献

1 Eschenmoser A Angew Chem Int 1969 8 343

2 Eschenmoser A Pure Appl Chem 1969 20 1

3R Eschenmoser A Quart Rev 1970 24 366

4 Eschenmoser A Helv Chim Acta 1971 54 710

5 Shiosaki K Compreh Org Synth 1991 2 865

6 Horikawa H Tet Lett 1994 35 2187

7 Gaurat O Can J Chem 2004 82 1289

编译自：Organic Syntheses Based On Name Reactions, 3RdEd, A. Hassner, Page 143.