反应详情

To a solution of 6-bromo-3′-methylspiro[chroman-2,1′-cyclopentan]-4-one (216 mg, 0.73 mmol) in anhydrous DCM (5.7 mL) was added TiCl4 (1 M solution in DCM, 1.5 mL, 1.49 mmol) dropwise within 15 min at room temperature. The mixture was stirred forl h after the addition. To this mixture was added bis-trimethylsilylcarbodiimide (300 mg, 0.36 mL, 1.61 mmol) dropwise. The resulting mixture was stirred for another 18 h after the addition. The reaction mixture was poured into ice-water (20 g) and extracted with DCM (3×20 mL). The combined organic phases were dried over anhydrous Na2S O4, filtered, and concentrated to give (E)-N-(6-bromo-3′-methylspiro[chroman-2,1′-cyclopentane]-4-ylidene)cyanamide as light brown solid (225 mg), which was used in the next step without further purification.

1. additionafter the addition
2. stirringThe resulting mixture was stirred for another 18 h
3. additionafter the addition
4. extractionextracted with DCM (3×20 mL)
5. customThe combined organic phases were dried over anhydrous Na2S O4
6. filtrationfiltered
7. concentrationconcentrated