◊ The co-authors are based on the chronical order worked on this project
Abstract
The Wolff–Kishner reduction, discovered in the early 1910s, is a fundamental and effective tool to convert carbonyls into methylenes via deoxygenation under strongly basic conditions. For over a century, numerous valuable chemical products have been synthesized by this classical method. The reaction proceeds via the reversible formation of hydrazone followed by deprotonation with the strong base to give an N-anionic intermediate, which affords the deoxygenation product upon denitrogenation and protonation. By examining the mechanistic pathway of this century old classical carbonyl deoxygenation, we envisioned and subsequently developed two unprecedented new types of chemical transformations: a) alcohol deoxygenation and b) C–C bond formations with various electrophiles including Grignard-type reaction, conjugate addition, olefination, and diverse cross-coupling reactions.
1 Introduction
2 Background
3 Alcohol Deoxygenation
3.1 Ir-Catalyzed Alcohol Deoxygenation
3.2 Ru-Catalyzed Alcohol Deoxygenation
3.3 Mn-Catalyzed Alcohol Deoxygenation
4 Grignard-Type Reactions
4.1 Ru-Catalyzed Addition of Hydrazones with Aldehydes and Ketones
4.2 Ru-Catalyzed Addition of Hydrazone with Imines
4.3 Ru-Catalyzed Addition of Hydrazone with CO2
4.4 Fe-Catalyzed Addition of Hydrazones
5 Conjugate Addition Reactions
5.1 Ru-Catalyzed Conjugate Addition Reactions
5.2 Fe-Catalyzed Conjugate Addition Reactions
6 Cross-Coupling Reactions
6.1 Ni-Catalyzed Negishi-type Coupling
6.2 Pd-Catalyzed Tsuji–Trost Alkylation Reaction
7 Other Reactions
7.1 Olefination
7.2 Heck-Type Reaction
7.3 Ullmann-Type Reaction
8 Conclusion and Outlook
Keywords alkylation - carbanions - catalysis - cross-coupling - deoxygenation - Grignard reaction - hydrazones - nucleophilic addition