Palladium-Catalyzed Enantioselective Addition of Chiral Metal Enolates to In Situ Generated Ortho-Quinone Methides.

We describe herein a conceptually novel, cooperative Brønsted acid-base catalyzed process for the conjugate addition of cyclic β-keto esters to in situ generated ortho-quinone methides. Upon hemiacetalization densely functionalized chiral chromans with two adjacent quaternary and additionally a tertiary stereogenic center were obtained with very good diastereoselectivity (up to >95:5 d.r.) and typically excellent enantioselectivity (up to >99% ee). The striking feature and key to success is the dual catalytic activation of both nucleophile and electrophile in two separate cycles with a single chiral catalyst. PMID: 30278112 [PubMed - as supplied by publisher]
Source: Angewandte Chemie - Category: Chemistry Authors: Tags: Angew Chem Int Ed Engl Source Type: research
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