Photochemical Synthesis of Acetals utilizing Schreiner’s Thiourea as the Catalyst

Acetalization of aldehydes is an area of great importance in Organic Chemistry for both synthetic and biological puproses. Herein, we report a mild, inexpensive and green photochemical protocol, where Schreiner’s thiourea (N,N′-bis[3,5-bis(trifluoromethyl)-phenyl]-thiourea) is utilized as the catalyst and cheap household lamps as the light source. A variety of aromatic and aliphatic aldehydes have been converted into acyclic and cyclic acetals in good to high yields. The reaction mechanism was also studied.