Free Radical Allyl Transfers Utilizing Soluble Non-Cross-Linked Polystyrene and Carbohydrate Scaffold Supports

Enholm, Eric J.; Gallagher, Maria E.; Jiang, Shaojun; Batson, William A.

doi:10.1021/ol006449e

Cited by 39 publications

(25 citation statements)

References 20 publications

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“…[2][3][4][5][6][7][8][9][10][11] We have recently demonstrated that triethylborane has the potential to induce the intermolecular radical reactions on solid support. 12,13) Moreover, the employment of triethylborane and its related radical initiator such as diethylzinc at low reaction temperature would facilitate the control of stereochemistry in solidphase reactions.…”

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confidence: 99%

Solid-Phase Tandem Radical Addition-Cyclization Reaction: Triethylborane-Induced Reaction of Oxime Ethers Anchored to Polymer Support

Miyabe

Naito

2004

CHEMICAL & PHARMACEUTICAL BULLETIN

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Solid-phase radical reactions have been developed for an important carbon-carbon bond-forming method on solid support under mild reaction conditions. [2][3][4][5][6][7][8][9][10][11] We have recently demonstrated that triethylborane has the potential to induce the intermolecular radical reactions on solid support. 12,13) Moreover, the employment of triethylborane and its related radical initiator such as diethylzinc at low reaction temperature would facilitate the control of stereochemistry in solidphase reactions.14,15) As a part of our program directed toward the solid-phase radical reactions, the development of solid-phase multi bonds-forming reactions has been the new focus of our efforts. We report here in detail the triethylborane-induced tandem radical addition-cyclization reaction of oxime ethers anchored to polymer support. 16,17) Free radical-mediated cyclization has been developed as a powerful method for preparing various types of cyclic compounds via carbon-carbon bond-forming processes. [18][19][20][21][22][23][24][25][26][27][28][29] Our laboratory is interested in developing the effective and convenient methods for the synthesis of highly functionalized cyclic compounds. For this purpose, we have studied the radical reaction using oxime ether group as a radical acceptor. [30][31][32][33][34][35][36] Particularly, strategies involving the radical addition-cyclization reactions offer the advantage of the formation of multiple carbon-carbon and carbon-heteroatom bonds in a single operation.We recently reported the carbon radical addition-cyclization of oxime ethers connected with the a,b-unsaturated carbonyl group and the heteroatom radical addition-cyclization reaction of oxime ethers having an olefin moiety (Fig. 1). [37][38][39][40] Based on these results, we have studied the tandem radical addition-cyclization of oxime ethers (TYPE 1 and TYPE 2) anchored to polymer support. 16,17) In this paper, we report the radical addition-cyclization reaction of oxime ether (TYPE 1). To enhance the reactivity of resin-bound substrates, we introduced a temporary spacer generated from glutaric anhydride. 41) Results and DiscussionPreparation of oxime ether 4 anchored to a polymer support is shown in Chart 1. The reaction of a-chloroacetaldoxime ether 1, which was prepared from chloroacetaldehyde and O-benzylhydroxyamine hydrochloride, 42) with allylamine gave the secondary amine 2 in 76% yield. The amine 2 was treated with glutaric anhydride to give the oxime ether 3 as an E/Z mixture concerning oxime ether moiety in a 3 : 2 ratio. In our recent studies on the radical reaction of oxime ethers, we have observed no remarkable effect of the geometry of the starting oxime ether group on either the chemical yield or stereoselectivity by employing geometrically pure E and Z-isomers. 32) Thus, oxime ether 3 was subjected to the following reactions without the separation of E/Z-isomers. Wang resin purchased from Novabiochem was used. The oxime ether 3 having the spacer moiety was attached to Wang resin by treatment wi...

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confidence: 99%

Solid-Phase Tandem Radical Addition-Cyclization Reaction: Triethylborane-Induced Reaction of Oxime Ethers Anchored to Polymer Support

Miyabe

Naito

2004

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…Therefore the extension of carbon-carbon bond-forming radical reactions to solid-phase reactions would allow further progress in combinatorial organic synthesis. 60,64) In addition to some reports on solid-state radical cyclizations using 2,2Ј-azobisisobutyronitrile (AIBN) or SmI 2 as a radical initiator, 65,66) Sibi's group reported the first studies on the solid-phase intermolecular radical reaction using allyl stannanes and AIBN. 67) To test the viability of triethylborane as a radical initiator on solid support, we first investigated the radical addition to the oxime ether 54 anchored to Wang resin and TentaGel OH resin (Chart 20).…”

Section: Radical Reaction Of Imine Derivatives In Aqueous Mediamentioning

confidence: 99%

Development of New Synthetic Reactions for Nitrogen-Containing Compounds and Their Application

Naito

2008

Chem. Pharm. Bull.

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Nitrogen-containing compounds are core parts not only of natural and synthetic medicines but also of biologically active compounds including natural products. This review focuses on the development of new synthetic reactions for nitrogen-containing compounds via three methodologies: the reductive photocycloaddition reaction of enamides, radical addition reaction, and nucleophilic addition reaction. Newly developed reactions were successfully applied to the synthesis of various types of nitrogen-containing compounds including medicines, lead compounds to new drugs, natural alkaloids, and others.

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“…[2] Although enantiomerically pure compounds [3] are of major interest for the pharmaceutical industry only few stereoselective syntheses on the solid-phase have been reported so far. Besides polymer-bound chiral ligands and catalysts [4] some immobilized chiral auxiliaries and their application in aldol condensations, [5] conjugate additions, [6] 1,3-dipolar cycloadditions, [7] or radical allylations [8] have been described.…”

Section: Gernot Zech and Horst Kunz*mentioning

confidence: 99%

Stereoselective Solid‐Phase Synthesis of Chiral Piperidine Derivatives by Using an Immobilized Galactose Auxiliary

Zech

Kunz

2003

Angew Chem Int Ed

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Free Radical Allyl Transfers Utilizing Soluble Non-Cross-Linked Polystyrene and Carbohydrate Scaffold Supports

Cited by 39 publications

References 20 publications

Solid-Phase Tandem Radical Addition-Cyclization Reaction: Triethylborane-Induced Reaction of Oxime Ethers Anchored to Polymer Support

Solid-Phase Tandem Radical Addition-Cyclization Reaction: Triethylborane-Induced Reaction of Oxime Ethers Anchored to Polymer Support

Development of New Synthetic Reactions for Nitrogen-Containing Compounds and Their Application

Stereoselective Solid‐Phase Synthesis of Chiral Piperidine Derivatives by Using an Immobilized Galactose Auxiliary

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