The reaction of hydroquinone and monosubstituted hydroquinones with dimethyl chloromalonate
Abstract
Hydroquinone and monosubstituted hydroquinones free from –I,–M groups react with dimethyl chloromalonate in methanolic sodium methoxide solution to give 2-oxido-benzo[b]furan derivatives (1). The mechanism of this base catalysed C-alkylation is interpreted in terms of initial mono-O-alkylation followed by fragmentation and 1,4-addition of dimethyl sodiomalonate to the nascent 1,4-benzoquinone so formed. The procedure furnishes, in moderate to high yield, products which cannot be prepared readily by direct nucleophilic addition to 1,4-benzoquinones.