Tetrahedron Letters

Mild and efficient boronic acid catalysis of Diels–Alder cycloadditions to 2-alkynoic acids

H Zheng, DG Hall

Index: Zheng, Hongchao; Hall, Dennis G. Tetrahedron Letters, 2010 , vol. 51, # 27 p. 3561 - 3564

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Citation Number: 36

Abstract

The concept of boronic acid catalysis (BAC) for the activation of unsaturated carboxylic acids is applied to the Diels–Alder cycloaddition between 2-alkynoic acids as dienophiles and various dienes. These [4+ 2] cycloadditions produce cyclohexadienyl carboxylic acids, which can be oxidized in situ to produce polysubstituted aromatic carboxylic acids. The boronic acid catalyst is suspected to provide activation by a LUMO-lowering effect of the ...