تفاعل #74389

معادلة التفاعل

phosphorus-trichloride

Tygon

sodium sulfite

(1S,4R)-bicyclo[2.2.1]heptane-2-carboxylic acid

bromine

→

(4S)-2-bromobicyclo[2.2.1]heptane-1-carboxylic acid

المذيبات

ether

ظروف التفاعل

المعالجة

1. 1
   workup.ADDITIONAfter the addition
2. 2
   درجة الحرارةthe reaction mixture was heated in a silicone oil bath at 80° C. for 4 h
3. 3
   درجة الحرارةAfter this time, the reaction was cooled to 10° C.
4. 4
   درجة الحرارةThe reaction was then heated to 80° C
5. 5
   درجة الحرارةThe reaction was then cooled to room temperature
6. 6
   أخرىThe ethereal solution was transferred to a separation funnel
7. 7
   غسيلwashed with 1M sodium sulfite (2 (500 mL), water (1 (500 mL), and brine (1 (500 mL)
8. 8
   تجفيفThe organic layer was dried over MgSO4
9. 9
   ترشيحfiltered
10. 10
    تركيزconcentrated in vacuo
11. 11
    أخرىto afford an oil
12. 12
    workup.STIRRINGthe mixture was stirred vigorously
13. 13
    workup.WAITAfter 20 min
14. 14
    أخرىa fine white precipitate formed
15. 15
    ترشيحwhich was filtered
16. 16
    غسيلwashed with pentane (20 mL)
17. 17
    أخرىair dried under a gentle vacuum

الإجراء التجريبي

To a 50 mL round-bottomed flask was added (1S,4R)-bicyclo[2.2.1]heptane-2-carboxylic acid (9.84 g, 70 mmol) and bromine (4.10 ml, 80 mmol). The suspension was stirred at room temperature until dissolution. Trichlorophosphine (0.30 ml, 3.4 mmol) was then added slowly and drop wise (significant exotherm observed). A reflux condenser was fitted to the flask with a nitrogen gas inlet and gas outlet (Tygon tubing) running into a scrubber solution of sodium sulfite (1 M, 200 mL). After the addition was complete, the reaction mixture was heated in a silicone oil bath at 80° C. for 4 h. After this time, the reaction was cooled to 10° C. and phosphorus-trichloride (4.23 ml, 48.3 mmol) was added drop-wise. The reaction was then heated to 80° C. During this time the color intensity of the reaction decreased, and after 8 h, the reaction mixture appeared dark orange. The reaction was then cooled to room temperature and diluted with ether (1 L). The ethereal solution was transferred to a separation funnel and washed with 1M sodium sulfite (2 (500 mL), water (1 (500 mL), and brine (1 (500 mL). The organic layer was dried over MgSO4, filtered, and concentrated in vacuo to afford an oil. Ice cold pentane (50 mL) was then added to the crude product, and the mixture was stirred vigorously. After 20 min, a fine white precipitate formed, which was filtered and washed with pentane (20 mL) and then air dried under a gentle vacuum to afford (4S)-2-bromobicyclo[2.2.1]heptane-1-carboxylic acid (100.2 g, 457 mmol) as a white solid material.

المصدر