RESUMO
Using dimethylsulfoxonium methylide as the methylene transfer reagent, 2a,8b-dihydrobenzo[b]cyclobute[d]pyran-3-ones were converted into 2,2'-biphenol derivatives as major products and dihydrodibenzofurans as minor products. The reaction mechanism was extrapolated from a deuteration experiment with CD2=S(O)(CD3)2.
Assuntos
Ciclobutanos/química , Dibenzofuranos/síntese química , Fenóis/síntese química , Compostos de Sulfônio/química , Dibenzofuranos/química , Estrutura Molecular , Fenóis/químicaRESUMO
By applying a skeleton transformation reaction using dimethylsulfoxonium methylide, a novel reaction was identified by which 5,6,7,8-tetrahydrocoumarin with the electron-withdrawing group at C3 was led to the spirobicyclo[3.1.0]hexane-cyclohexane derivative. Moreover, by establishing the scope of this reaction, it was confirmed that it is possible to apply this reaction to not only ring-fused α-pyrone derivatives but also alkyl-chain-substituted α-pyrone derivatives in moderate to good yields.
Assuntos
Compostos Bicíclicos com Pontes/síntese química , Hexanos/química , Pironas/química , Compostos de Espiro/síntese química , Compostos de Sulfônio/química , Compostos Bicíclicos com Pontes/química , Estrutura Molecular , Compostos de Espiro/química , EstereoisomerismoRESUMO
The first asymmetric total synthesis of (-)-Linderol A, a potent inhibitor of melanin biosynthesis of cultured B-16 melanoma cells, has been achieved via two key reactions: a diastereoselective [2+2] photocycloaddition of a coumarin-3-carboxylate bearing a chiral auxiliary with 3-methyl-1-butene and a subsequent stereoconvergent transformation of the photoadducts with use of dimethylsulfoxonium methylide to afford a tetrahydrodibenzofuran derivative.