Pinacol coupling of aromatic aldehydes and ketones using TiCl3–Mg under ultrasound irradiation

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 8–95% yields within 15–40 min under ultrasound irradiation.