2H-Chromenes from Salicylaldehydes by a Catalytic Petasis Reaction

Qian Wang and M. G. Finn*

*Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, Email: mgfinngatech.edu

Q. Wang, M. G. Finn, Org. Lett., 2000, 2, 4063-4065.

DOI: 10.1021/ol006710r

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Abstract

The Petasis condensation of vinylic or aromatic boronic acids, salicylaldehydes, and amines is assisted by the hydroxy group adjacent to the aldehyde moiety. A subsequent cyclization with ejection of amine upon heating provides 2H-chromenes. A catalytic method using a resin-bound amine enables a convenient preparation of 2H-chromenes.

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proposed mechanism with HNBn₂ as catalyst

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Key Words

Petasis reaction, 2H-chromenes, organocatalysis

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ID: J54-Y2000