Diastereo- and Enantioselective Synthesis of 2,2-Disubstituted Benzofuran-3-one Bearing Adjacent Quaternary and Tertiary Stereocenters

The first highly diastereo- and enantioselective synthesis of armeniaspirol analogues was achieved using L-proline derived bifunctional squaramide which outperformed commonly used organocatalysts. Excellent yield (up to 99%) with diastereoselectivity (up to 99:1) and enantioselectivity (up to 99%) were obtained for a wide range of substrates.