Reductive Coupling Cyclization Research Articles

Divergent synthesis of chromones and chromanones from diketones using an AgOTf/[Si]H system by switching hydrosilanes

A method of using AgOTf/[Si]H for the efficient and divergent synthesis of chromones and chromanones from a common substrate via reductive coupling cyclization by switching hydrosilanes has been developed. Results of mechanistic studies revealed that under Ph2MeSiH conditions, the reaction initially undergone cyclization to form chromones 2a, which can subsequently be reduced to yield chromanones 3a. When the hydrosilane was switched to Et3SiH, the reaction route stopped at chromone 2a and C2C3 could not be further reduced. This novel, mild protocol features broad functional group compatibility, high product diversity, and utility in constructing biorelevant chromone or chromanone derivatives.

ChemInform Abstract: Tosylhydrazine Mediated Conjugate Reduction and Sequential Reductive Coupling Cyclization: Synthesis of 2‐Arylchromans.

Abstract Tosylhydrazine mediated conjugate reduction of 2-hydroxyl chalcones and sequential reductive coupling cyclization is described. This is an unprecedented protocol and an extremely efficient method for a one-pot domino synthesis of 2-arylchromans in good to excellent yields from commercially available, cheap starting materials. More importantly, the two-step reactions can be easily controlled to afford dihydrochalcones or 2-arylchromans by the mole amounts of tosylhydrazine. Furthermore, the operational simplicity of the process and the high functional group tolerance are remarkable.

Tosylhydrazine mediated conjugate reduction and sequential reductive coupling cyclization: synthesis of 2-arylchromans

Tosylhydrazine mediated conjugate reduction of 2-hydroxyl chalcones and sequential reductive coupling cyclization is described. This is an unprecedented protocol and an extremely efficient method for a one-pot domino synthesis of 2-arylchromans in good to excellent yields from commercially available, cheap starting materials. More importantly, the two-step reactions can be easily controlled to afford dihydrochalcones or 2-arylchromans by the mole amounts of tosylhydrazine. Furthermore, the operational simplicity of the process and the high functional group tolerance are remarkable.

Intermolecular Couplization and Cyclization of Chalcones Promoted by Samarium in DMF

Under mild and neutral conditions, reductive coupling–cyclization of chalcones was promoted by samarium metal with an activator in DMF to afford products in good to excellent yields. The reaction is regioselective over the competitive carbon–carbon double-bond reduction and stereocontrolled.

Samarium‐Mediated Reductive Coupling Cyclization of α‐Phenylsulfonylcinnamonitriles Catalyzed by Viologen under Room Temperature Conditions.

Promoted by metallic samarium and catalyzed by viologen, the intermolecular reductive coupling cyclization reactions of α-phenylsulfonylcinnamonitriles were studied. A possible reaction mechanism was proposed.

Samarium Mediated Reductive Coupling Cyclization of α-Phenylsulfonylcinnamonitriles Catalyzed by Viologen Under Room Temperature Conditions

Promoted by metallic samarium and catalyzed by viologen, the intermolecular reductive coupling cyclization reactions of α-phenylsulfonylcinnamonitriles were studied. A possible reaction mechanism was proposed.

Intermolecular Reductive Coupling Cyclization of 1,1,Diaryl‐2,2‐dicyanoethylenes with Aldehydes or Ketones to Synthesize Polysubstituted 2,3‐Dihydrofurans and Cyclopentenylamines Promoted by Samarium Metal in DMF.

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Reductive Coupling Cyclization of 1,1‐Dicyanoalkenes Promoted by Sm0/cat. HgCl2 System

AbstractThe intermolecular reductive coupling cyclization reactions of 1,1‐dicyanoalkenes promoted by Sm0/cat. HgCl2 were studied. A possible reaction mechanism was proposed.

ChemInform Abstract: Novel Reductive Coupling Cyclization of 1,1‐Dicyanoalkenes Promoted by Metallic Samarium in Aqueous Media.

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Novel reductive coupling cyclization of 1,1-dicyanoalkenes promoted by metallic samarium in aqueous media

The reductive coupling cyclization of 1,1-dicyanoalkenes was performed with metallic samarium in saturated aqueous NH 4Cl-THF solution at room temperature. Sub-stoichiometric quantities of samarium could be employed and trans-isomer was the major product.