Photoinduced electron transfer ring opening of a-epoxyketones using 7,7,8,8-tetracyano-p-quinodimethane (TCNQ) in methanol and acetic acid solutions resulted in the formation of diastereomeric products, hydroxy ethers and hydroxy esters, respectively. However, the formation of cis-1,3-dioxolanes and cis-spirodioxolanes has been observed on reaction in acetone and cyclohexanone solutions, respectively. The effect of the electron donating character of the substituent influenced the rate of the ring opening. Quantum computational studies explain the mechanism of the addition.
