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An efficient one-pot synthesis of indenes from simple starting materials is presented. This process involves a dual C-C bond formation through an intermolecular Heck coupling reaction followed by acid-mediated intramolecular cyclodehydration. The strategy is amenable to various substituted aro- matics to give indenes. In addition, the regioselective synthesis of benzyl styrenes in a single column purification technique through in-situ reduction of Heck products (ketones) followed by acid mediated dehydration of crude reaction mixture is presented. [ABSTRACT FROM AUTHOR]

Abstract: A new approach to the synthesis of highly substituted cyclopentadienes, indenes, and cyclopentene‐fused heteroarenes by means of the Pd‐catalyzed Trost–Oppolzer‐type intramolecular Alder–ene reaction of 2,4‐pentadienyl acetates is described. This unprecedented transformation combines the electrophilic features of the Tsuji–Trost reaction with the nucleophilic features of the Alder–ene reaction. The overall outcome can be perceived as a hitherto unknown “acid‐free” iso‐Nazarov‐type cyclization. The versatility of this strategy was further demonstrated by the formal synthesis of paucifloral F, a resveratrol‐based natural product. [ABSTRACT FROM AUTHOR]

A new and versatile multicomponent domino strategy has been developed for the synthesis of a series of 1H-indene and phthalimide derivatives from simple and readily available starting materials. This process operating under mild conditions shows a broad substrate scope with moderate to excellent yields. [ABSTRACT FROM AUTHOR]

A novel synthesis of 1,1-disubstituted 1H-indenes is described involving the Pd-catalyzed cascade reaction between o-bromophenyl-β-bromostyrenes and N-tosylhydrazones in a process comprising the consecutive formation of two Csp³-C bonds on the same carbon atom: the cross-coupling of the N-tosylhydrazone with the alkenyl bromide and the intramolecular Heck reaction on the newly formed double bond. A similar approach has been applied to the preparation of 1,1-disubstituted naphthalenes. [ABSTRACT FROM AUTHOR]

Densely functionalized alkylidene indanes and indanones can be prepared efficiently in one pot, in high yields with good stereoselectivities (in some cases exclusively the Z-isomer), through a route involving phosphine-catalyzed Michael addition followed by palladium-catalyzed Heck cyclization. These transformations tolerate substrates bearing various substituents around the indane/indanone motif. Employing this technology, a concise formal synthesis of sulindac, a nonsteroidal anti-inflammatory drug, has been established. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics including application of a dual catalytic system in the Wittig reaction, gold acyl complex formation during indene synthesis, and palladium catalyzed arylation of allylamines.

An efficient tandem route to the synthesis of 2,2a1,4-triazacyclopenta[ cd]indene derivatives of the cyclazine family has been developed. The target compounds were obtained in moderate to good yields by an ytterbium(III) triflate/palladium(II) acetate-catalyzed three-component domino reaction involving a palladium-catalyzed intramolecular α-arylation of an α-aminocarbonyl functionality. This in turn will set the stage for a wide application of this useful reaction for the synthesis of structurally diverse polyheterocyclic skeletons containing the privileged imidazo[1,2- a]pyridine structure. [ABSTRACT FROM AUTHOR]

A Pd(II)/Brønsted acid catalyzed migratory ring expansion for the synthesis of indene derivatives possessing a stereogenic spirocyclic carbon center was developed. This transformation is believed to mechanistically proceed via enantioselective allylic C-H activation with concomitant semipinacol ring expansion to the nascent π-allylpalladium species. Enantioselectivities as high as 98% ee were attainable. [ABSTRACT FROM AUTHOR]

Intramolecular Pd-catalyzed cyclization of various o-(alkynyl)styrenes includes bromopalladation/Heck cross-coupling/β-H elimination using oxygen as an oxidant affords 3-bromoindenes of type (II). [ABSTRACT FROM AUTHOR]

Palladium-catalyzed intramolecular carbonylative annulation of 1-(2-iodophenyl)-1,3-diones using phenyl formate as the CO source furnishes the title compounds. [ABSTRACT FROM AUTHOR]

The reaction provides dihydrocyclopenta[a]indene derivatives endowed with various aryl substituents in high yields. [ABSTRACT FROM AUTHOR]

The synthesis of cyclazines involves initial three-component condensation and a Pd-catalyzed intramolecular α-arylation of an α-aminocarbonyl functionality. [ABSTRACT FROM AUTHOR]