On treatment of alkyl aryl sulfoxides with alkylmetals (alkyllithium or Grignard reagent) sulfuralkyl or sulfur-aryl bond-cleavage takes place to give new alkylmetals or arylmetals. This reaction is called sulfoxide-metal exchange reaction. In this paper, the author mainly reviews the new methods for the generation of magnesium carbenoids and alkylmagnesiums having a heteroatom on their a-position by the sulfoxide-magnesium exchange reaction.
When the alkyl aryl sulfoxides have a heteroatom (such as Cl, O, N) on the α-position in the alkyl group, the reaction with alkylmetals results in the sulfur-alkyl bond cleavage to give a carbenoids and/or α-heteroatom-substituted carbanions at low temperature in high yields. Especially, magnesium carbenoids are quite interesting compounds and some novel synthetic reactions have been developed
via the carbenoids. The sulfoxide-magnesium exchange reaction of sulfinylaziridines gave the stable aziridinylmagnesiums, from which a new synthesis of both enantiomers of the optically active amines having a quaternary chiral center was realized. A new synthesis of olefins and allenes, including optically active form, from sulfoxides and alkenyl sulfoxides, and carbonyl compounds by the sulfoxide-magnesium exchange reaction is also reviewed.
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