Ligand-Free Ru-Catalyzed Direct sp 3 C-H Alkylation of Fluorene Using Alcohols

The sp C-H alkylation of 9 -fluorene using alcohol and a Ru catalyst via the borrowing hydrogen concept has been described. This reaction was catalyzed by the [Ru( -cymene)Cl ] complex (3 mol %) and exhibited a broad reaction scope with different alcohols, allowing primary and secondary alcohols to...

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Bibliographic Details
Published in:Journal of organic chemistry 2020-02, Vol.85 (4), p.2277-2290
Main Authors: Shaikh, Moseen A, Agalave, Sandip G, Ubale, Akash S, Gnanaprakasam, Boopathy
Format: Article
Language:English
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Summary:The sp C-H alkylation of 9 -fluorene using alcohol and a Ru catalyst via the borrowing hydrogen concept has been described. This reaction was catalyzed by the [Ru( -cymene)Cl ] complex (3 mol %) and exhibited a broad reaction scope with different alcohols, allowing primary and secondary alcohols to be employed as nonhazardous and greener alkylating agents with the formation of environmentally benign water as a byproduct. A variety of 9 -fluorene underwent selective and exclusive mono-C9-alkylation with primary alcohols in good to excellent isolated yield (26 examples, 50-92% yield), whereas this reaction with secondary alcohols in the absence of any external oxidants furnished the tetrasubstituted alkene as the major product. Furthermore, a base-mediated C-H hydroxylation of the synthesized 9 -fluorene derivatives afforded 9 -hydroxy-functionalized quaternary fluorene derivatives in excellent yield.
ISSN:0022-3263
1520-6904
DOI:10.1021/acs.joc.9b02913