Intramolecular reaction

About: Intramolecular reaction is a research topic. Over the lifetime, 5015 publications have been published within this topic receiving 138213 citations.

Asymmetric Synthesis of Hydrobenzofuranones via Desymmetrization of Cyclohexadienones Using the Intramolecular Stetter Reaction

Abstract: Dearomatization of phenols followed by oxidation affords cyclohexadienyloxyacetaldehydes, which produce hydrobenzofuranones via asymmetric intramolecular Stetter reaction in good to excellent yield. Quaternary as well as up to three contiguous stereocenters may be formed in good to excellent enantioselectivities and high diastereoselectivities.

Palladium-catalyzed method for the synthesis of carbazoles via tandem C-H functionalization and C-N bond formation.

Abstract: The development of a new method for the assembly of unsymmetrical carbazoles is reported. The strategy involves the selective intramolecular functionalization of an arene C-H bond and the formation of a new arene C-N bond. The substitution pattern of the carbazole product can be controlled by the design of the biaryl amide substrate, and the method is compatible with a variety of functional groups. The utility of the new protocol was demonstrated by the concise synthesis of three natural products from commercially available materials.

Biaryl Synthesis via Direct Arylation: Establishment of an Efficient Catalyst for Intramolecular Processes

Abstract: In this Communication, we describe direct arylation reactions with improved scope and catalyst activity for the intramolecular formation of biaryl compounds. This was achieved through the establishment of a highly active and robust catalyst system and the subsequent development of a novel phosphine ligand 27. The enhanced catalytic activity extends these transformations to include previously unreactive and poorly reactive substrates, and allows for very low catalyst loadings to be employed-as little as 0.1 mol %.

Intramolecular reactions of alkynes with furans and electron rich arenes catalyzed by PtCl2: the role of platinum carbenes as intermediates.

Abstract: 5-(2-Furyl)-1-alkynes react, with PtCl2 as catalyst, to give phenols. On the basis of DFT calculations, a cyclopropyl platinacarbene complex was found as the key intermediate in the process. The cyclopropane and dihydrofuran rings of this intermediate open to form a carbonyl compound, which reacts with the platinum carbene to form an oxepin, which is in equilibrium with an arene oxide. When the reaction is carried out in the presence of water, dicarbonyl compounds are obtained, which support the proposed mechanism. Other cyclizations of alkynes with furans or electron-rich arenes give products of apparent Friedel−Crafts-type reactions, although these processes could also proceed by pathways involving the formation of cyclopropyl platinum carbenes.

Highly efficient and enantioselective cyclization of aromatic imines via directed C-H bond activation.

Abstract: The first highly enantioselective catalytic reaction involving aromatic C−H bond activation is communicated. Enantioselective cyclization of aromatic ketimines containing alkenyl groups tethered at the meta position of an imine directing group has been achieved using 5 mol % [RhCl(coe)2]2 and 15 mol % of an (S)-binol-derived phosphoramidite ligand. Selectivities of up to 96% ee and up to quantitative yields were obtained. Moreover, the identified catalyst system enables the intramolecular alkylation reaction to be performed at temperatures 75 °C lower than our previously reported achiral system. The reaction can even be performed at room temperature for one of the optimal substrates.