Tetrahedron

Conjugate addition to 3-(ptolylsulphinyl) chromone: a route to 2-substituted chromones and chiral substituted chroman-4-ones

ST Saengchantara, TW Wallace

Index: Saengchantara, Suthiweth T.; Wallace, Timothy W. Tetrahedron, 1990 ,  vol. 46,  # 18  p. 6553 - 6564

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Citation Number: 31

Abstract

3-(p-Tolylsulphinyl) chromone 3a undergoes diastereoselective conjugate addition 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% ee Chelation of the carbonyl and sulphoxide oxygens during methyl addition ...