反应详情

To a solution of 6-bromo-2-phenylchroman-4-one (1.016 g, 3.35 mmol) in anhydrous DCM under N2 atmosphere was added 1 M TiCl4 (in DCM, 6.7 mL, 6.7 mmol) dropwise within 15 min at room temperature. The mixture was stirred for 1 h after the addition. To this mixture was added bis-trimethylsilylcarbodiimide (1.374 g, 7.37 mmol) dropwise. The resulting mixture was stirred for another 24 h after the addition. The reaction mixture was poured into ice-water (100 g), stirred for a while and filtered through a pad of Celite. The filtrate was extracted with DCM (3×30 mL). The combined organic phases were dried over anhydrous Na2SO4, filtered, and concentrated to give (E)-N-(6-bromo-2-phenylchroman-4-ylidene)cyanamide as light brown solid (899 mg), which was used in the next step without further purification. MS ESI+ve m/z 327 (M+H)+.

1. additionafter the addition
2. stirringThe resulting mixture was stirred for another 24 h
3. additionafter the addition
4. stirringstirred for a while
5. filtrationfiltered through a pad of Celite
6. extractionThe filtrate was extracted with DCM (3×30 mL)
7. dry with materialThe combined organic phases were dried over anhydrous Na2SO4
8. filtrationfiltered
9. concentrationconcentrated