Abstract 1, 4-Benzoquinones and 1, 4-naphthoquinones carrying 3′, 3′-dimethyloxiranyl, dimethylacetyl or oxiranylmethyloxy substituents (1, 2 or 3) have been synthesized. The methods presented involved epoxidation of a sterically overcrowded double bond as a crucial step for synthesis of (3′, 3′-dimethyloxiranyl) quinones 1. Reaction of aryllithium derivatives with 2-chloro-2-methyl-propanol unexpectedly led to (dimethyl) acetylarenes ...