In the investigation of efficient chemical transformations, the carbon-carbon bond-forming reactions play an outstanding role. In this context, organocatalytic processes have achieved considerable attention. 1 Beside their facile reaction course, selectivity, and environmental friendliness, new synthetic strategies are made possible. Particularly, the inversion of the classical reactivity (Umpolung) opens up new synthetic pathways. 2 In nature, the coenzyme thiamine (vitamin B1), a natural thiazolium salt, utilizes a catalytic variant of this concept in biochemical processes as nucleophilic acylations. 3 The catalytically active species is a nucleophilic carbene. 4

Organocatalysis by N-Heterocyclic Carbenes

Asymmetric enamine catalysis.

Small-molecule H-bond donors in asymmetric catalysis.

4.2.8. Reductive Coupling 3109 5. Reaction of Aromatic Compounds 3110 5.1. Electrophilic Substitutions 3110 5.2. Radical Substitution 3111 5.3. Oxidative Coupling 3111 5.4. Photochemical Reactions 3111 6. Reaction of Carbonyl Compounds 3111 6.1. Nucleophilic Additions 3111 6.1.1. Allylation 3111 6.1.2. Propargylation 3120 6.1.3. Benzylation 3121 6.1.4. Arylation/Vinylation 3121 6.1.5. Alkynylation 3121 6.1.6. Alkylation 3121 6.1.7. Reformatsky-Type Reaction 3122 6.1.8. Direct Aldol Reaction 3122 6.1.9. Mukaiyama Aldol Reaction 3124 6.1.10. Hydrogen Cyanide Addition 3125 6.2. Pinacol Coupling 3126 6.3. Wittig Reactions 3126 7. Reaction of R,â-Unsaturated Carbonyl Compounds 3127

Organic Reactions in Aqueous Media with a Focus on Carbon−Carbon Bond Formations: A Decade Update

Over the past decade, the most significant, conceptual advances in the field of fluorination were enabled most prominently by organo- and transition-metal catalysis. The most challenging transformation remains the formation of the parent C-F bond, primarily as a consequence of the high hydration energy of fluoride, strong metal-fluorine bonds, and highly polarized bonds to fluorine. Most fluorination reactions still lack generality, predictability, and cost-efficiency. Despite all current limitations, modern fluorination methods have made fluorinated molecules more readily available than ever before and have begun to have an impact on research areas that do not require large amounts of material, such as drug discovery and positron emission tomography. This Review gives a brief summary of conventional fluorination reactions, including those reactions that introduce fluorinated functional groups, and focuses on modern developments in the field.

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Introduction of Fluorine and Fluorine-Containing Functional Groups

We describe a catalytic method for the synthesis of a variety of functionalized aliphatic acid esters using silylperoxyacetals, which are versatile alkyl radical precursors with a terminal ester moiety. In the presence of an appropriate transition-metal catalyst, the in situ generation of alkyl radicals and the subsequent bond-forming process proceeds smoothly to afford synthetically valuable aliphatic acid derivatives. The present method can be applied to the efficient synthesis of a pharmaceutically important 1,1-diarylalkane motif. In addition, a novel strategy for the synthesis of structurally diverse hydroxy acid derivatives via a C-O bond formation process that utilizes TEMPO has been developed.

Synthesis of Functionalized Aliphatic Acid Esters via the Generation of Alkyl Radicals from Silylperoxyacetals.

Carbonyl‐Lewis Acid Complexes

Epoxy Silyl Ether Rearrangements: A New, Stereoselective Approach to the Synthesis of β-Hydroxy Carbonyl Compounds.

Zr(OBut)4 as a New Promoter for the Meerwein-Ponndorf-Verley Alkynylation and Cyanation of Aldehydes

The axially chiral biphenols are known as a broadly applicable chiral source. However, only a few electron-deficient ones have been reported to date. In the present study, chiral biphenols having s...

Keiji Maruoka

Papers

Synthesis of Functionalized Aliphatic Acid Esters via the Generation of Alkyl Radicals from Silylperoxyacetals.

Carbonyl‐Lewis Acid Complexes

Epoxy Silyl Ether Rearrangements: A New, Stereoselective Approach to the Synthesis of β-Hydroxy Carbonyl Compounds.

Zr(OBut)4 as a New Promoter for the Meerwein-Ponndorf-Verley Alkynylation and Cyanation of Aldehydes

Synthesis of Electron-Deficient Chiral Biphenols and Their Applications in Catalytic Asymmetric Reactions.