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Modular pyridine synthesis from oximes and enals through synergistic copper/iminium catalysis.

Journal of the American Chemical Society (2013-02-27)
Ye Wei, Naohiko Yoshikai
ABSTRACT

We describe here a [3+3]-type condensation reaction of O-acetyl ketoximes and α,β-unsaturated aldehydes that is synergistically catalyzed by a copper(I) salt and a secondary ammonium salt (or amine). This redox-neutral reaction allows modular synthesis of a variety of substituted pyridines under mild conditions with tolerance of a broad range of functional groups. The reaction is driven by a merger of iminium catalysis and redox activity of the copper catalyst, which would initially reduce the oxime N-O bond to generate a nucleophilic copper(II) enamide and later oxidize a dihydropyridine intermediate to the pyridine product.

MATERIALI
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Descrizione del prodotto

Sigma-Aldrich
Piridina, ACS reagent, ≥99.0%
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Piridina, suitable for HPLC, ≥99.9%
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Pyridine hydrochloride, 98%
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Piridina, ≥99%
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Piridina, biotech. grade, ≥99.9%
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Pyridine hydrobromide, 98%
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Piridina, analytical standard
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Pyridine solution, certified reference material, 2000 μg/mL in methanol
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Pyridine hydrochloride, purum, ≥98.0% (AT)