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

A novel approach for asymmetric synthesis of both enantiomeric aldol products has been developed by designing two different chiral organocatalysts from a readily available, protected cis-diamine compound as a common chiral source. This approach would be very useful from a practical viewpoint.

Complete Switch of Product Selectivity in Asymmetric Direct Aldol Reaction with Two Different Chiral Organocatalysts from a Common Chiral Source.

PROBLEM TO BE SOLVED: To provide a compound which is a new optically-active binuclear ammonium salt obtained by replacing ammonium spread to both sides of a biphenyl skeleton with axially asymmetric biphenyl residues and exerts an excellent effect as a phase transfer catalyst in synthesis of optically-active amino acid regardless of natural or non-natural, and also to provide an intermediate useful for production of the same. SOLUTION: This compound is an optically-active ammonium salt shown by formula (1), and there are provided a biphenyl compound, a diamine compound and the like as intermediates useful for production of the ammonium salt of formula (1). COPYRIGHT: (C)2005,JPO&NCIPI

Optically-active ammonium salt compound and intermediate for production thereof

The first transformation of β,γ-unsaturated carboxylic acids to γ-butenolides according to the title reaction is elaborated.

Keiji Maruoka

Papers

Complete Switch of Product Selectivity in Asymmetric Direct Aldol Reaction with Two Different Chiral Organocatalysts from a Common Chiral Source.

Optically-active ammonium salt compound and intermediate for production thereof

A Chiral Electrophilic Selenium Catalyst for Highly Enantioselective Oxidative Cyclization.

Binaphthyl‐ and Biphenyl‐Modified Chiral Phase‐Transfer Catalysts for Asymmetric Synthesis

Asymmetric Phase‐Transfer and Ion Pair Catalysis