반응 #430108

반응 방정식

sodium sulfite

p-toluenesulfonamide

(DHQ)2 -PHAL

acrylate

Chloramine-T trihydrate

→

Chloramine-T

용매

acetonitrile

water

반응 조건

후처리

1. 1
   기타proceeded to completion over the course of about one and half hours at room temperature
2. 2
   기타the phases were separated
3. 3
   추출the aqueous phase extracted with ethyl acetate (3×15 mL)
4. 4
   세척The combined organic extracts were washed with brine
5. 5
   건조dried over MgSO4
6. 6
   농축the solvent concentrated
7. 7
   기타to give the crude product, which

실험 절차

To a stirred solution of (DHQ)2 -PHAL (0.11 g, 0.14 mmol, 5 mol %) in 20 mL of acetonitrile and 20 mL of water, in any convenient-sized glass vessel or vial, was added desired acrylate or methacrylates entries 1-10 (all commercially available from Aldrich, FIG. 16 and FIG. 17, 2.8 mmol), Chloramine-T trihydrate (2.42 g, 8.4 mmol, 3 eq) and K2OsO2 (OH)4 (41.6 mg, 0.112 mmol, 4 mol %). As the reaction proceeded to completion over the course of about one and half hours at room temperature, the color of the solution changed from yellow to pale green, then deep green and finally back to yellow. After addition of aqueous sodium sulfite (1.0 g in 15 mL H2O), the phases were separated, and the aqueous phase extracted with ethyl acetate (3×15 mL). The combined organic extracts were washed with brine, dried over MgSO4 and the solvent concentrated to give the crude product, which also contains the p-toluenesulfonamide by-product produced upon the reduction of the excess Chloramine-T. Purification provides compounds as shown in FIG. 16, entries 1-10 with the indicated yields and conditions. NOTE: Replacement of the 3 eq of Chloramine-T with 1.5 eq of Chloramine-T and 1.5 eq of Et4NOAc gives comparable results and reduces the amount of p-toluenesulfonamide by-product formed. This can greatly simplify product isolation, especially in cases where the product and the toluenesulfonamide have similar chromatographic mobilities. ##STR17##

출처