- Ruthenium-Catalyzed α-Alkylation of Ketones Using Secondary Alcohols to β-Disubstituted Ketones
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An assortment of aromatic ketones was successfully functionalized with a variety of unactivated secondary alcohols that serve as alkylating agents, providing β-disubstituted ketone products in good to excellent yields. Remarkably, challenging substrates such as simple acetophenone derivatives are effectively alkylated under this ruthenium catalysis. The substituted cyclohexanol compounds displayed product-induced diastereoselectivity. Mechanistic studies indicate the involvement of the hydrogen-borrowing pathway in these alkylation reactions. Notably, this selective and catalytic C-C bond-forming reaction requires only a minimal load of catalyst and base and produces H2O as the only byproduct, making this protocol attractive and environmentally benign.
- Thiyagarajan, Subramanian,Vijaya Sankar, Raman,Gunanathan, Chidambaram
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supporting information
p. 7879 - 7884
(2020/11/02)
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- Iron-Catalyzed α-Alkylation of Ketones with Secondary Alcohols: Access to β-Disubstituted Carbonyl Compounds
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An iron-catalyzed borrowing hydrogen strategy has been applied in the synthesis of β-branched carbonyl compounds. Various secondary benzylic and aliphatic alcohols have been used as alkylating reagents under mild reaction conditions. The ketones have been
- Bettoni, Léo,Gaillard, Sylvain,Renaud, Jean-Luc
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supporting information
(2020/03/13)
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- Catalytic Cross-Coupling of Secondary Alcohols
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Herein, an unprecedented ruthenium(II) catalyzed direct cross-coupling of two different secondary alcohols to β-disubstituted ketones is reported. Cyclic, acylic, symmetrical, and unsymmetrical secondary alcohols are selectively coupled with aromatic benzylic secondary alcohols to provide ketone products. A single catalyst oxidizes both secondary alcohols to provide selectively β-disubstituted ketones to broaden the scope of this catalytic protocol. Number of bond activation and bond formation reactions occur in selective sequence via amine-amide metal-ligand cooperation operative in Ru-MACHO catalyst. The product-induced diastereoselectivity was also observed. Kinetic and deuterium labeling experiments suggested that the aliphatic secondary alcohols undergo oxidation reaction faster than benzylic secondary alcohols, selectively assimilating to provide the cross-coupled products. Reactions are sensitive to steric hindrance. This new C-C bond forming methodology requires low catalyst load and catalytic amount of base. Notably, the reaction produces H2 and H2O as the only byproducts making the protocol greener, atom economical and environmentally benign.
- Thiyagarajan, Subramanian,Gunanathan, Chidambaram
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supporting information
p. 3822 - 3827
(2019/04/09)
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- Ruthenium-Catalyzed Direct Cross-Coupling of Secondary Alcohols to β-Disubstituted Ketones
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The β-disubstituted ketone functionality is prevalent in biologically active compounds and in pharmaceuticals. A ruthenium-catalyzed direct synthesis of β-disubstituted ketones by cross-coupling of two different secondary alcohols is reported. This new protocol was applied to the synthesis of variety of β-disubstituted ketones from various cyclic, acyclic, symmetrical, and unsymmetrical secondary alcohols. An amine-amide metal-ligand cooperation in a Ru catalyst facilitates the activation and formation of covalent bonds in selective sequences to provide the products. Kinetic and deuterium-labeling experiments suggested that aliphatic alcohols oxidize faster than benzylic secondary alcohols. A plausible mechanism is proposed on the basis of mechanistic and kinetic studies. Water and H 2 are the only byproducts from this selective cross-coupling of secondary alcohols. 1 Introduction 2 Catalytic Self-or Cross-Coupling of Alcohols and Selectivity Challenges 3 Recent Developments in the Synthesis of β-Disubstituted Ketones 4 Scope of Ruthenium-Catalyzed Cross-Couplings of Secondary Alcohols 5 Mechanistic Studies and Proposed Mechanism 6 Conclusion.
- Gunanathan, Chidambaram,Thiyagarajan, Subramanian
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p. 2027 - 2034
(2019/11/05)
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- Addition conjuguee d'organometalliques sur des mesitylcetones α-ethyleniques
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Reactions of α-ethylenic mesitylketones with a series of organometallic compounds including allylic orgnometallics and organolithium compounds proceed via exclusive conjugated additions as a result of the steric congestion of the carbonyl of these ketones
- Barbot, F.,N'Goma, D.,Miginiac, Ph.
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p. 277 - 286
(2007/10/02)
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