Intramolecular Radical Cyclization of Vinyl, Aryl and Alkyl Halides Using Catalytic Amount of Bis-tri-n-butyltin Oxide/Sodium Borohydride: A Novel Entry to Functionalized Carbocycles

We wish to report a facile method in which a catalytic amount of bis-tri-n-butyltinoxide (TBTO) in the presence of sodium borohydride efficiently brings about the intramolecular radical cyclization of a variety of vinyl, aryl and alkyl halides to their corresponding functionalized bicyclic and tricyclic carbocycle frameworks. The methodology obviates the need for stoichiometric amounts of tin reagent normally required for radical cyclization reactions.

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Intramolecular Radical Cyclization of Vinyl, Aryl and Alkyl Halides Using Catalytic Amount of Bis-tri-n-butyltin Oxide/Sodium Borohydride: A Novel Entry to Functionalized Carbocycles

Synlett ◽

10.1055/s-0034-1378728 ◽

2015 ◽

Vol 26 (10) ◽

pp. 1426-1426

Author(s):

Namasivayam Palani ◽

Sengottuvelan Balasubramanian ◽

Tarur Dinesh

Keyword(s):

Sodium Borohydride ◽

Catalytic Amount ◽

Radical Cyclization ◽

Alkyl Halides

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ChemInform Abstract: Intramolecular Radical Cyclization of Vinyl, Aryl and Alkyl Halides Using Catalytic Amount of Bis-tri-n-butyltin Oxide/Sodium Borohydride: A Novel Entry to Functionalized Carbocycles.

ChemInform ◽

10.1002/chin.201537040 ◽

2015 ◽

Vol 46 (37) ◽

pp. no-no

Author(s):

Tarur Konikkaledom Dinesh ◽

Namasivayam Palani ◽

Sengottuvelan Balasubramanian

Keyword(s):

Sodium Borohydride ◽

Catalytic Amount ◽

Radical Cyclization ◽

Alkyl Halides

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Activation modes in biocatalytic radical cyclization reactions

Journal of Industrial Microbiology & Biotechnology ◽

10.1093/jimb/kuab021 ◽

2021 ◽

Author(s):

Yuxuan Ye ◽

Haigen Fu ◽

Todd K Hyster

Keyword(s):

Heme Iron ◽

Radical Cyclization ◽

Cytochrome P450 Monooxygenases ◽

Radical Cyclizations ◽

Cyclization Reactions ◽

Complex Molecules ◽

P450 Monooxygenases ◽

Non Heme Iron ◽

Essential Reactions ◽

Isopenicillin N

Abstract Radical cyclizations are essential reactions in the biosynthesis of secondary metabolites and the chemical synthesis of societally valuable molecules. In this review, we highlight the general mechanisms utilized in biocatalytic radical cyclizations. We specifically highlight cytochrome P450 monooxygenases (P450s) involved in the biosynthesis of mycocyclosin and vancomycin, non-heme iron- and α-ketoglutarate-dependent dioxygenases (Fe/αKGDs) used in the biosynthesis of kainic acid, scopolamine, and isopenicillin N, and radical S-adenosylmethionine (SAM) enzymes that facilitate the biosynthesis of oxetanocin A, menaquinone, and F420. Beyond natural mechanisms, we also examine repurposed flavin-dependent ‘ene’-reductases (ERED) for non-natural radical cyclization. Overall, these general mechanisms underscore the opportunity for enzymes to augment and enhance the synthesis of complex molecules using radical mechanisms.

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