Catalytic enantioselective Michael addition of 2-substituted benzofuran-3-ones to 2-enoyl pyridines?

Organic & Biomolecular Chemistry Pub Date: 2019-07-10 DOI: 10.1039/C9OB01069F

Abstract

An organocatalytic diastereo- and enantioselective synthesis of 2,2′-disubstituted benzofuran-3-ones bearing adjacent quaternary and tertiary stereocenters has been achieved through Michael addition of 2-substituted benzofuran-3-ones to 2-enoyl pyridines. Both the enantiomeric forms of the major diastereomer were obtained using L-proline derived squaramide and quinine derived bis squaramide with excellent yield (up to 98%) and stereoselectivities (up to 97?:?3 dr and 98% ee). The control experiment revealed that the presence and position of nitrogen atoms in the 2-enoylpyridine have played a crucial role in the stereochemical outcome of the product.

Graphical abstract: Catalytic enantioselective Michael addition of 2-substituted benzofuran-3-ones to 2-enoyl pyridines
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