Dehydrogenation as a substrate-activating strategy in homogeneous transition-metal catalysis.

Hydrogen autotransfer in the N-alkylation of amines and related compounds using alcohols and amines as electrophiles.

Alcohols can be temporarily converted into carbonyl compounds by the metal-catalysed removal of hydrogen. The carbonyl compounds are reactive in a wider range of transformations than the precursor alcohols and can react in situ to give imines, alkenes, and α-functionalised carbonyl compounds. The metal catalyst, which had borrowed the hydrogen, then returns it to the transformed carbonyl compound, leading to an overall process in which alcohols can be converted into amines, compounds containing CC bonds and β-functionalised alcohols.

Borrowing hydrogen in the activation of alcohols

The borrowing hydrogen (BH) principle, also called hydrogen auto-transfer, is a powerful approach which combines transfer hydrogenation (avoiding the direct use of molecular hydrogen) with one or more intermediate reactions to synthesize more complex molecules without the need for tedious separation or isolation processes. The strategy which usually relies on three steps, (i) dehydrogenation, (ii) intermediate reaction, and (iii) hydrogenation, is an excellent and well-recognized process from the synthetic, economic, and environmental point of view. In this context, the objective of the present review is to give a global overview on the topic starting from those contributions published prior to the emergence of the BH concept to the most recent and current research under the term of BH catalysis. Two main subareas of the topic (homogeneous and heterogeneous catalysis) have been identified, from which three subheadings based on the source of the electrophile (alkanes, alcohols, and amines) have been consid...

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Advances in One-Pot Synthesis through Borrowing Hydrogen Catalysis

The reactivity of alcohols can be enhanced by the temporary removal of hydrogen using a transition metal catalyst to generate an intermediate aldehyde or ketone. The so-formed carbonyl compound has a greater reactivity towards nucleophilic addition accommodating the in situ formation of imines or alkenes. The return of hydrogen from the catalyst leads to the formation of new C-N and C-C bonds, often with water as the only reaction by-product.

https://www.researchgate.net/profile/Michael_Whittlesey/publication/23804098_Transition_metal_catalysed_reactions_of_alcohols_using_borrowing_hydrogen_methodology/links/00b7d524052bad61c9000000.pdf

Transition metal catalysed reactions of alcohols using borrowing hydrogen methodology

[Ru(DMSO)4]Cl2 catalyzes the α-alkylation of ketones by alcohols

The electrophilic α-alkylation of ketones with alcohols was accomplished by a [Ru(DMSO) 4 ]Cl 2 catalyzed process, water being the only wasted material. The reaction can be successfully governed to produce either the expected ketones or their related alcohols only by changing the reaction conditions. When 2-aminobenzyl alcohol was used, a cyclization process took place to yield 2,3-disubstituted quinolines.

[Ru(DMSO)4]Cl2 Catalyzes the α‐Alkylation of Ketones by Alcohols.

Based on the synthesis of stereoisomers and spectroscopic comparison, it is found that the natural compound is represented by structure (I).

Gabriel J. Brand

Papers

[Ru(DMSO)4]Cl2 catalyzes the α-alkylation of ketones by alcohols

[Ru(DMSO)4]Cl2 Catalyzes the α‐Alkylation of Ketones by Alcohols.

Enantioselective Total Synthesis of the Unnatural and the Natural Stereoisomers of Vittalalactone.