Abstract
The catalytic, enantioselective, [4 + 2] cycloaddition reaction of ortho-quinone methides with silyl ketene acetals is described. This mechanistically interesting reaction, initiated by a chiral cinchona alkaloid-derived ammonium fluoride "precatalyst" complex, affords a variety of alkyl- and aryl-substituted 3,4-dihydrocoumarin products in excellent yield and with good enantioselectivity.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Alkaloids / chemistry
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Ammonium Compounds
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Catalysis
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Cyclization
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Fluorides / chemistry*
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Indolequinones / chemical synthesis*
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Indolequinones / chemistry
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Quaternary Ammonium Compounds / chemistry*
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Stereoisomerism
Substances
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Alkaloids
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Ammonium Compounds
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Indolequinones
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Quaternary Ammonium Compounds
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quinone methide
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ammonium fluoride
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Fluorides