Bulletin of the Chemical Society of Japan · 1995 · 31 citations · 7 references
DerivativesHeterocyclicBiochemistry1,2-Aryl ShiftNatural SciencesBenzene-sulfuric AcidOrganic ChemistryNew SynthesisAbstract FlavanonesPhytochemicalChemistryHeterocycle ChemistryPhytochemistryPharmacologySynthetic ChemistryHypervalent Iodine OxidationVariable RatiosNatural Product Synthesis
Abstract Flavanones (1), on oxidation with (diacetoxyiodo)benzene-sulfuric acid (DIB–H2SO4) or (hydroxy)tosyloxy)iodo)benzene (HTIB) in trimethyl orthoformate, undergo facile ring contraction by 1,2-aryl shift, thereby yielding methyl 2-aryl-2,3-dihydrobenzofuran-3-carboxylates (4) as major products (40—80%). cis-3-Methoxyflavanones (5) and flavones (3) are the minor products formed in variable ratios.
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