Intramolecular Direct Arylation of 1,3‐Diketone‐Derived Enol Ethers in a Synthesis of Tricyclic Oxoisochromene Derivatives

Abstract

A synthesis of tricyclic oxoisochromene derivatives via an intramolecular direct arylation of cycloalkyl‐1,3‐diketone‐derived α,β‐unsaturated ketone substrates is described. Interesting mechanistic insight has been gathered, based on deuterium migration studies, induced by palladium (Pd).magnified image

Brønsted Acid‐Mediated Formal [3+3] Annulation Between Propargylic Alcohols and 1,3‐Diketones

“…Three‐component reactions of aromatic aldehydes with 1,3‐cyclohexanediones and indoles for the facile assembly of the corresponding products using L‐proline as the catalyst have been developed by the Gu group (Scheme b) . Recently, McGlacken and co‐workers reported an elegant protocol for the synthesis of oxoisochromene derivatives through an intramolecular, one‐step arylation of α,β ‐unsaturated ketones (Scheme c) . Therefore, the search for practical and convenient synthetic approaches for the generation of chromenone derivatives from easily prepared starting materials is still an attractive target for synthetic organic chemists.…”

Novel oxoisochromene synthesisviachemoselective O–H insertion of 1,3-dicarbonyl compounds and subsequent Pd-catalyzed intramolecular arylation reaction

“…Recently, McGlacken and co-workers synthesized vinyl ethers bearing aryl halides via O -alkylation of 1,3-diketones with benzyl bromides. 15 However, these reactions, in some cases, provided low yields of vinyl ethers due to the formation of the C -alkylated product. These vinyl ethers were subsequently utilized for the synthesis of tricyclic oxoisochromene derivatives.…”

A palladium-catalyzed cascade approach for the synthesis of 3,3a,4,6,7,8,9,9a-octahydro-1H-benzo[f]isoindole-1,5(2H)-diones

“…11 McGlacken reported that 1,3-diketone-derived enol ethers could undergo Heck cyclization, offering tricyclic oxoisochromene derivatives in good yields (Scheme 1b). 12 In these cases, the introduction of a halogen atom into certain molecules was necessary. 15,16 Meanwhile, reports on alkylations at the αposition of enones and their derivatives are comparatively scarce.…”

“…[6][7][8][9][10] Recently, the α-arylation of enones and their derivatives has been developed. [11][12][13][14] For example, Liu reported an efficient synthesis of N-fused polycyclic indoles via a palladium-catalyzed annulation/ acyl migration cascade reaction (Scheme 1a). 11 McGlacken reported that 1,3-diketone-derived enol ethers could undergo Heck cyclization, offering tricyclic oxoisochromene derivatives in good yields (Scheme 1b).…”