Abstract
A new type of Baylis–Hillman adducts derived from chlorovinyl aldehydes were prepared via Vilsmeier reaction of ketones with a bis(trichloromethyl) carbonate (BTC)/DMF system to construct chlorovinyl aldehydes, followed by sonochemical Baylis–Hillman reaction under solvent-free conditions. The stereoselective bromination of these new compounds with a Br2-Ph3P system has been achieved efficiently with good to excellent yields under mild conditions.
ACKNOWLEDGMENTS
We thank the National Key Technology Research and Development Program (No. 2007BAI34B00) and the National Natural Science Foundation of China (No. 20676123) for financial support.
Notes
a Reaction conditions: 1 (100.0 mmol), BTC (100.0 mmol), DMF (300.0 mmol), and chloroform (100 mL) were used.
b Isolated yields based on 1.
a Reaction conditions: 2a (50.0 mmol), 3a (100.0 mmol), base (10.0 mmol), and solvent (50 mL) were used.
b Isolated yields based on 2a.
c In the absence of ultrasound.
a Reaction conditions: 2 (50.0 mmol), 3 (100.0 mmol), and DABCO (10.0 mmol) were used.
b Isolated yields based on 2.
c In the absence of ultrasound.
a Reaction conditions: 4a (10.0 mmol), bromination reagents (10.0 mmol), and solvents (30 mL) were used.
b Isolated yields.
a Reaction conditions: 4 (10.0 mmol), Br2 (10.0 mmol), Ph3P (10.0 mmol), and CH2Cl2 (30 mL) were used.
b Isolated yields.