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An iterative generation of o-quinone methides (o-QMs) and [4+2] cycloaddition followed by inter/intra-molecular Michael addition in a cascade sequence gave expedient access to total synthesis of myristinins A–F and 3′-hydroxy-5,7-dimethoxy-4-O-2′-cycloflavan and their analogues, respectively. This cascade sequence cyclisation successfully provided the shortest route to the gram-scale synthesis of the myristinin family, including the first total synthesis of myristinin D–F and 3′-hydroxy-5,7-dimethoxy-4-O-2′-cycloflavan. [ABSTRACT FROM AUTHOR]

We report a practical and efficient method for the synthesis of bioactive flavanoids relying on the strategic use of o-quinine methide (o-QM) intermediates. This involves Brønsted acid-catalysed iterative generation of o-QMs/[4+2] cycloaddition/intermolecular Michael addition/cyclative acetalization in a cascade sequence for the synthesis of dioxabicyclo[3.3.1]nonanes. The 'one-pot', controlled cascade sequence successfully provided the shortest route amenable for gram scale synthesis of natural products (±)-myristicyclins A–B. [ABSTRACT FROM AUTHOR]

The TMSOTf catalyzed intramolecular [4+2] cycloaddition of in situ generated aza‐o‐quinone methide allows an expedient, stereoselective access to cis/trans‐fused furo/pyrano[3,2‐c]tetrahydroquinolines with excellent yields and diastereoselectivity. The geometry of the dienophile olefin was found to have a profound effect on the stereochemical outcome of these reactions. [ABSTRACT FROM AUTHOR]

A substrate dependent regio‐ and stereoselective domino hydroalkoxylation‐formal‐[4+2] cycloaddition is described for the facile synthesis of linear as well as spirocyclic 1,4‐heterocycle‐fused chromene ketals. Enantiospecific synthesis of oxazepino chromene derivatives was successfully carried out using chiral pool amino alkynols. The developed hydroalkoxylation cascade offered rapid access to the spirocyclic [6‐6‐7‐6] tetracyclic core of cytorhizhins B–D with correct relative configuration. [ABSTRACT FROM AUTHOR]

B The Front Cover b shows bird eggs (product) with their parents (reactants). GLO:5AG/30nov20:ejoc202001247-toc-0001.jpg PHOTO (COLOR): . gl B The Front Cover b shows bird eggs (product) with their parents (reactants). These quinoline derivatives are core structures of pharmaceutically relevant chemical tools and therapeutic agents. [Extracted from the article]