Gold-catalyzed intramolecular cyclization of alkynones with pyridine anhydrobases

Pawar, Lokesh; Pigge, F. Christopher

doi:10.1016/j.tetlet.2013.08.110

Cited by 18 publications

(8 citation statements)

References 39 publications

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“…[9] Main approaches to this class of compounds include C−H oxidation reactions[ 9a , 9b , 9c ] and intramolecular cyclization reactions (Scheme 1 b ). [ 9d , 9e , 9f , 9g , 9h ] Despite these significant advances, still limitations exist with respect to substrate scope and the use stoichiometric amounts of oxidants or additives.…”

Section: Introductionmentioning

confidence: 99%

Palladium‐Catalyzed Cascade Carbonylation to α,β‐Unsaturated Piperidones via Selective Cleavage of Carbon–Carbon Triple Bonds

Yang

et al. 2021

Angew Chem Int Ed

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Ad irect and selective synthesis of a,b-unsaturated piperidones by an ew palladium-catalyzed cascade carbonylation is described. In the presented protocol, easily available propargylic alcohols react with aliphatic amines to provide abroad variety of interesting heterocycles.Key to the success of this transformation is ar emarkable catalytic cleavage of the present carbon-carbon triple bond by using aspecific catalyst with 2-diphenylphosphinopyridine as ligand and appropriate reaction conditions.M echanistic studies and control experiments revealed branched unsaturated acid 11 as crucial intermediate. Scheme 1. a) Summary of the main catalytic methods for CCcleavage. b) Summary of the main currently available synthetic methods for a,b-unsaturated piperidones. c) This work. d) Selected examples of biologically active molecules.

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Section: Introductionmentioning

confidence: 99%

Palladium‐Catalyzed Cascade Carbonylation to α,β‐Unsaturated Piperidones via Selective Cleavage of Carbon–Carbon Triple Bonds

Yang

et al. 2021

Angew Chem Int Ed

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“…Main approaches to this class of compounds include C−H oxidation reactions [9a–c] and intramolecular cyclization reactions (Scheme 1 b). [9d–h] Despite these significant advances, still limitations exist with respect to substrate scope and the use stoichiometric amounts of oxidants or additives.…”

Section: Introductionmentioning

confidence: 99%

Palladium‐Catalyzed Cascade Carbonylation to α,β‐Unsaturated Piperidones via Selective Cleavage of Carbon–Carbon Triple Bonds

Yang

et al. 2021

Angewandte Chemie

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A direct and selective synthesis of α,β‐unsaturated piperidones by a new palladium‐catalyzed cascade carbonylation is described. In the presented protocol, easily available propargylic alcohols react with aliphatic amines to provide a broad variety of interesting heterocycles. Key to the success of this transformation is a remarkable catalytic cleavage of the present carbon–carbon triple bond by using a specific catalyst with 2‐diphenylphosphinopyridine as ligand and appropriate reaction conditions. Mechanistic studies and control experiments revealed branched unsaturated acid 11 as crucial intermediate.

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“…19 As part of general efforts aimed at developing new synthetic methods for construction and manipulation of aza-heterocyclic ring systems, we have been examining the reactivity of pyridine and related aza-arene anhydrobases (i.e., 7, Scheme 1). We have found that activation of 4-alkylpyridines with an electrophile under mildly basic conditions can afford alkylidene dihydropyridines (anhydrobases) that are capable of participating in a variety of intramolecular C−C bond forming transformations, including aldol-like condensations, 20 Au-catalyzed cyclizations, 21 and Pd-catalyzed Heck reactions. 22 Similar electrophilic activation of 2-alkylimidazoles has also been demonstrated.…”

Section: ■ Introductionmentioning

confidence: 99%

Alkylidene Dihydropyridines As Synthetic Intermediates: Model Studies toward the Synthesis of the Bis(piperidine) Alkaloid Xestoproxamine C

2016

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Results of model studies demonstrating a stereoselective synthetic route to tricyclic analogues of the bis(piperidine) alkaloid xestoproxamine C are presented. Dearomatization of a tricyclic pyridine derivative to afford an alkylidene dihydropyridine (anhydrobase) intermediate followed by catalytic heterogeneous hydrogenation was used to install the correct relative stereochemistry about the bis(piperidine) ring system. Other key features of these model studies include development of an efficient ring-closing metathesis procedure to prepare macrocyclic derivatives of 3,4-disusbstituted pyridines, intramolecular cyclizations of alkylidene dihydropyridines to establish pyridine-substituted pyrrolidines and piperidines, successful homologation of pyridine-4-carboxaldehydes using formaldehyde dimethyl thioacetal monoxide (FAMSO), and application of B-alkyl Suzuki coupling to assemble substituted pyridines.

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Gold-catalyzed intramolecular cyclization of alkynones with pyridine anhydrobases

Cited by 18 publications

References 39 publications

Palladium‐Catalyzed Cascade Carbonylation to α,β‐Unsaturated Piperidones via Selective Cleavage of Carbon–Carbon Triple Bonds

Palladium‐Catalyzed Cascade Carbonylation to α,β‐Unsaturated Piperidones via Selective Cleavage of Carbon–Carbon Triple Bonds

Palladium‐Catalyzed Cascade Carbonylation to α,β‐Unsaturated Piperidones via Selective Cleavage of Carbon–Carbon Triple Bonds

Alkylidene Dihydropyridines As Synthetic Intermediates: Model Studies toward the Synthesis of the Bis(piperidine) Alkaloid Xestoproxamine C

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