反应详情

A 2.0 M oxalyl chloride in dichloromethane solution is prepared by adding with stirring 98% oxalyl chloride (110.0 mL) to anhydrous dichloromethane (600.0 mL). The resulting solution of oxalyl chloride (1.20 mol) is added dropwise over 1 h to a stirring solution of 2-methylcyclopropanecarboxylic acid (commercially available product which is a cis-trans mixture, 120.0 g, 1.20 mol) in toluene (800.0 mL) containing DMF (0.6 mL, 7.8 mmol). The mixture is stirred 2 h at room temperature; then it is added dropwise to a solution of benzyl alcohol (114.0 mL, 1.10 mol), anhydrous THF (800.0 mL), and pyridine (194.0 mL, 2.41 mol) over 1.5 h. The mixture is stirred 1 h longer after addition, partitioned between ethyl acetate (2 L) and 10% aqueous potassium carbonate (2 L); and the organic phase is washed (10% aqueous potassium carbonate (2 L) and brine (2 L)), dried (MgSO4) and evaporated to a liquid. Chromatography over silica gel, eluting with 5% ethyl acetate in hexanes, provides the major product, racemic benzyl trans-2-methyl-cyclopropanecarboxylate as a clear, colorless liquid (193.8 g, 93%).

1. additionby adding
2. stirringThe mixture is stirred 1 h
3. additionlonger after addition
4. custompartitioned between ethyl acetate (2 L) and 10% aqueous potassium carbonate (2 L)
5. washand the organic phase is washed (10% aqueous potassium carbonate (2 L) and brine (2 L))
6. dry with materialdried (MgSO4)
7. customevaporated to a liquid
8. washChromatography over silica gel, eluting with 5% ethyl acetate in hexanes