USE OF MENTHYL 2-METHOXYNAPHTHALENE-1-SULFINATES IN THE ANDERSEN SYNTHESIS OF OPTICALLY-ACTIVE SULFOXIDES - FACILE CLEAVAGE BY GRIGNARD-REAGENTS OF SOME AROMATIC METHYL ETHERS

The pure crystalline diastereomers (1R,2S,5R)-menthyl (R)- and (S)-2-methoxynaphthalene-1-sulfinate (1b) have been prepared and, by reaction with Grignard reagents (the Andersen procedure), converted into optically active alkyl and aryl 2-methoxynaphthyl sulfoxides in 67-77% yields. Use of an excess of Grignard reagent results in facile O-alkyl cleavage of the methoxy group to the corresponding naphthol or a competing loss of the alkyl-or aryl-sulfinyl group to form 2-methoxynaphthalene. Pure diastereomers of menthyl 2,7-dimethoxynaphthalene-1-sulfinate (2b) and menthyl 4-methoxynaphthalene-1-sulfinate (3b) have also been prepared and their reactions with Grignard reagents have been studied.