Aryl(chloro)methyl 4-tolyl sulfoxides: Synthesis and application to the synthesis of α-aryl ketones

Article abstract of DOI:10.1055/s-0031-1260251

Aryl(chloro)methyl 4-tolyl sulfoxides were synthesized from arylmethyl 4-tolyl sulfoxides in moderate-to-good yields by sequential treatment with lithium diisopropylamide and tosyl chloride at low temperatures. Treatment of the lithium α-sulfinyl carbanion of the aryl(chloro)methyl 4-tolyl sulfoxides with aldehydes or ketones resulted in the formation of adducts in good-to-high yields. Treatment of these adducts with tert-butylmagnesium chloride gave the corresponding magnesium alkoxides. On treatment with isopropylmagnesium chloride, the alkoxides gave the corresponding magnesium β-oxido carbenoids, which rearranged to give α-aryl ketones in good-to-high yields. The magnesium enolate intermediates generated by rearrangement of the -oxido carbenoids could also be trapped with electrophiles to give α-aryl α-substituted ketones. These procedures offer a good method for the synthesis of a variety of α-aryl ketones from aldehydes and ketones. Georg Thieme Verlag Stuttgart. New York.