Lithiation of 2-(chloroaryl)-2-methyl-1,3-dioxolanes and application in synthesis of new ortho-functionalized acetophenone derivatives

2-(4-Chlorophenyl)-2-methyl-1,3-dioxolane 2a was lithiated ortho to the ketal group by treatment with butyllithium in THF at 0°C. Related 2-aryl-2-methyl-1,3-dioxolanes possessing a chlorine substituent at the meta position of the aryl group 2b,c were lithiated with butyllithium in THF at −78°C at the position between the two directing groups. The lithio species thus generated were treated with various electrophiles to give ortho-functionalized acetophenone derivatives.