Expedient synthesis of xanthones and multi-functionalized chromones from 1,1-diacyl cyclopropanes

Synthetic Strategies towards the Synthesis of Oxyisocyclointegrin

“…In order to rapidly assess the viability of this approach, the model oxepine‐fused flavone 12 was constructed from commercially available 2‐hydroxyacetophenone using our previously disclosed procedure (Scheme ) …”

“…In addition, surprisingly, there are a limited number of methods to forge the fused‐oxepine ring described in the literature. To the best of our knowledge only two distinct strategies to access this substrate have been reported, namely an oxidative intramolecular cyclization strategy (transition metals, DDQ and photochemically mediated) and most recently, a Mitsunobu reaction . Given that several structurally similar substrates possess significant biological activity, we deemed the synthesis of oxyisocyclointegrin a worthy pursuit.…”

Synthesis of Seven Membered Oxacycles: Recent Developments and New Approaches

“…[53] In 2018, Hawkins and co-workers, exploited a method previously developed by them, [54] in combination with a cyclization under Mitsunobu conditions, [55] to get access to the oxepinefused flavone 133. [56] As depicted in Scheme 30, the first reaction transforms the cyclopropane 132 into the alcohol 137. This process takes place via the palladium-promoted cyclopropane opening, and the subsequent nucleophilic attack from the phenolate to the ketone in 135 to generate the intermediate 136, which finally undergoes a protonation and dehydration to yield the compound 137.…”

“…Adapted from ref. [56] In 2019, Hou, Gou and co-workers reported a sequence involving an intramolecular ring opening of cyclopropanes as a key step in forming 4-benzoyl-3,4-dihydrobenzo[b]oxepin-5(2H)-one derivatives 139 (Scheme 31). [57] Scheme 31.…”

“…In 2018, Hawkins and co‐workers, exploited a method previously developed by them, [ 54 ] in combination with a cyclization under Mitsunobu conditions, [ 55 ] to get access to the oxepine‐fused flavone 133 . [ 56 ]…”