反应详情

To a solution of 6-cyclohexyl-2′,4′,5′,6′-tetrahydrospiro[chroman-2,3′-pyran]-4-one (240 mg, 0.804 mmol) in anhydrous DCM (10 mL) was added TiCl4 (1 M solution in DCM, 608.6 mg, 3.2 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 (380.6 mg, 3.12 mmol) dropwise. The resulting mixture was stirred for another 18 h after the addition. The reaction mixture was poured into ice-water (100 g) and extracted with DCM (3×50 mL). The combined organic phases were dried over anhydrous Na2SO4, filtered, and concentrated to give (E)-N-(6-cyclohexyl-2′,4′,5′,6′-tetrahydrospiro[chroman-2,3′-pyran]-4-ylidene)cyanamide (20 mg, 10%), which was used for 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 (3×50 mL)
5. dry with materialThe combined organic phases were dried over anhydrous Na2SO4
6. filtrationfiltered
7. concentrationconcentrated