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 β-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.
sulfoxides - α-aryl ketones - homologations - aldehydes
