Multisubstituted α,β-Unsaturated γ-Lactones from 1-Chlorovinyl p-Tolyl Sulfoxides and tert-Butyl Carboxylates Using Pummerer-Type Cyclization as the Key Reaction
Multisubstituted α,β-Unsaturated γ-Lactones from 1-Chlorovinyl p-Tolyl Sulfoxides and tert-Butyl Carboxylates Using Pummerer-Type Cyclization as the Key Reaction
作者:Tsuyoshi Satoh、Takashi Katae、Shimpei Sugiyama
DOI:10.1055/s-0030-1259987
日期:2011.5
The addition reaction of 1-chlorovinyl p-tolyl sulfoxides, derived from aldehydes and chloromethyl p-tolyl sulfoxide, with the lithium enolate of tert-butyl carboxylates gave adducts in quantitative yields. Treatment of the adducts with trifluoroacetic anhydride in the presence of sodium iodide resulted in the formation of γ-lactones bearing a p-tolylsulfanyl group at the γ-position through Pummerer-type cyclization. Oxidation of the sulfanyl group to the sulfinyl group followed by thermal syn-elimination gave α,β-unsaturated γ-lactones (γ-butenolides) in moderate to good yields. Trapping the intermediates of the addition reaction with iodoalkanes gave alkylated adducts, from which α,γ- and β,γ-disubstituted γ-butenolides were obtained. These procedures provide a good way to synthesize multisubstituted γ-butenolides from aldehydes.