LVT Induced Pinacol Coupling Under Ultrasound Irradiation

Progress in piancol coupling of aldehydes and ketones using low valent titanium is reviewed in recent years. And we have researched the pinacol coupling reactions in ultrasound irradiation. This thesis consists of four parts. Part 1: Progress in piancol coupling of aldehydes and ketones using low valent titanium is reviewed in recent years. Several systems about pinacol coupling reactions have been reviewed, these systems including: pinacol coupling reactions with four value titanium or its complexes, three value titanium and two value titanium under ultrasound irradiation. Part 2: Titanium trichloride in EtOH or H2O can be reduced by Al to the corresponding low valent titanium complexes, which can reduce some aromatic aldehydes and ketones to the corresponding pinacols in 35-83% yields under ultrasound irradiation. Part 3: Titanium trichloride in EtOH can be reduced by Mg to the corresponding low valent titanium complexes, which can reduce some aromatic aldehydes and ketones to the corresponding pinacols in 20-95% yields under ultrasound irradiation. Part 4: The system of magnesium and magnesium iodide can reduce some aromatic aldehydes and ketones to the corresponding pinacols in good yields within 10-60 min at room temperature under ultrasound irradiation.