Enantioselective synthesis of 2,3-disubstituted trans-2,3-dihydrobenzofurans using a Brønsted base/thiourea bifunctional catalyst

摘要

The diastereo- and enantioselective synthesis of 2,3-disubstituted -2,3-dihydrobenzofuran derivatives (15 examples, up to 96:4 dr, 95:5 er) intramolecular Michael addition has been developed using keto-enone substrates and a bifunctional tertiary amine-thiourea catalyst. This methodology was extended to include non-activated ketone pronucleophiles for the synthesis of 2,3-disubstituted indane and 3,4-disubstituted tetrahydrofuran derivatives.