[Some recent advances in Pummerer-type reactions].

The Pummerer rearrangement of sulfoxides with acid anhydrides is a useful method for the synthesis of alpha-substituted sulfides and has attracted considerable attention from both synthetic and mechanistic points of view. In recent years, we have developed two novel and significant Pummerer-type reactions; i) an asymmetric Pummerer-type reaction of chiral, non-racemic sulfoxides with a highly enantiomeric excess, and ii) the first successful Pummerer-type reaction of the aromatic ring. In this review, we describe 1) the asymmetric Pummerer-type rearrangement induced by an O-silylated ketene acetal, 2) the asymmetric Pummerer-type rearrangement induced by an ethoxy vinyl acetate, 3) the additive-Pummerer-type reaction, 4) the asymmetric Pummerer-type cyclization induced by an O-silylated ketene acetal, and 5) the aromatic Pummerer-type reaction of p-sulfinyl phenol derivatives leading to peri-hydroxy dihydroquinone derivatives.