Conjugate addition to 3-(ptolylsulphinyl)chromone: a route to 2-substituted chromones and chiral substituted chroman-4-ones
作者:Suthiweth T. Saengchantara、Timothy W. Wallace
DOI:10.1016/s0040-4020(01)96020-x
日期:1990.1
3-(p-Tolylsulphinyl)chromone 3a undergoes diastereoselectiveconjugateaddition of lithium dimethylcuprate, producing a mixture of 2-methyl-3-(p-tolylsulphinyl)chroman-4-ones. Heating the mixture to 140°C gives 2-methylchromone in quantitative yield. Desulphurisation of the mixed products from (S)-3a gives (S)-2-methylchroman-4-one with 90% e.e. Chelation of the carbonyl and sulphoxide oxygens during