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

The ability of platinum and gold catalysts to effect powerful atom-economic transformations has led to a marked increase in their utilization. The quite remarkable correlation of their catalytic behavior with the available structural data, coordination chemistry, and organometallic reactivity patterns, including relativistic effects, allows the underlying principles of catalytic carbophilic activation by π acids to be formulated. The spectrum of reactivity extends beyond their utility as catalytic and benign alternatives to conventional stoichiometric π acids. The resulting reactivity profile allows this entire field of catalysis to be rationalized, and brings together the apparently disparate electrophilic metal carbene and nonclassical carbocation explanations. The advances in coupling, cycloisomerization, and structural reorganization—from the design of new transformations to the improvement to known reactions—are highlighted in this Review. The application of platinum- and gold-catalyzed transformations in natural product synthesis is also discussed.

Catalytic Carbophilic Activation: Catalysis by Platinum and Gold π Acids

Stronger Brønsted acids

Hydrogen bonding is responsible for the structure of much of the world around us. The unusual and complex properties of bulk water, the ability of proteins to fold into stable three-dimensional structures, the fidelity of DNA base pairing, and the binding of ligands to receptors are among the manifestations of this ubiquitous noncovalent interaction. In addition to its primacy as a structural determinant, hydrogen bonding plays a crucial functional role in catalysis. Hydrogen bonding to an electrophile serves to decrease the electron density of this species, activating it toward nucleophilic attack. This principle is employed frequently by Nature's catalysts, enzymes, for the acceleration of a wide range of chemical processes. Recently, organic chemists have begun to appreciate the tremendous potential offered by hydrogen bonding as a mechanism for electrophile activation in small-molecule, synthetic catalyst systems. In particular, chiral hydrogen-bond donors have emerged as a broadly applicable class of catalysts for enantioselective synthesis. This review documents these advances, emphasizing the structural and mechanistic features that contribute to high enantioselectivity in hydrogen-bond-mediated catalytic processes.

/pdf/asymmetric-catalysis-by-chiral-hydrogen-bond-donors-c4px56xxy0.pdf

Asymmetric catalysis by chiral hydrogen-bond donors.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/anie.200353240

Enantioselective Mannich‐Type Reaction Catalyzed by a Chiral Brønsted Acid

Hydrogen bond catalysis and Bronsted acid catalysis are rapidly growing areas in organocatalysis. A number of chiral acid catalysts has been developed recently. Recent progress in the chiral Bronsted acid catalysis has been reviewed with a focus being placed on thiourea, TADDOL, and phosphoric acids. 1  Introduction 2  Hydrogen Bond Catalysis 2.1 Monofunctional Thiourea Catalysts 2.2 Bifunctional Thiourea Catalysts 2.3 TADDOL Derivatives 2.4 BINOL Derivatives 3  Bronsted Acid Catalysis 3.1 Ammonium Salts 3.2 Phosphoric Acids 4  Conclusion

Recent Progress in Chiral Brønsted Acid Catalysis

Inverse electron-demand aza Diels−Alder reaction of aldimine with enol ethers proceeded under the influence of a phosphoric acid diester, derived from (R)-BINOL, to give tetrahydroquinoline derivatives with excellent enantioselectivity.

Chiral Brønsted Acid-Catalyzed Inverse Electron-Demand Aza Diels−Alder Reaction

Chiral Brønsted Acid Catalyzed Enantioselective Hydrophosphonylation of Imines: Asymmetric Synthesis of α-Amino Phosphonates

Mannich-type reaction of ketene silyl acetals with aldimines proceeded catalytically by means of a phosphoric acid diester, derived from (R)-BINOL, as a chiral Bronsted acid to afford β-amino esters with good diastereoselectivity in favor of the syn isomer and high enantioselectivity (up to 96% ee) The highest enantioselectivity was achieved by the phosphoric acid diester bearing 4-nitrophenyl groups on the 3,3‘-positions of BINOL The N-2-hydroxyphenyl group of aldimine was found to be essential for the present Mannich-type reaction In combination with these experimental investigations, two possible monocoordination and dicoordination pathways were explored using density functional theory calculations (BHandHLYP/6-31G*) The present reaction proceeds via a dicoordination pathway through the zwitterionic and nine-membered cyclic transition state (TS) consisting of the aldimine and the phosphoric acid The re-facial selectivity was also well-rationalized theoretically The nine-membered cyclic structure 

Kohei Fuchibe

Papers

Enantioselective Mannich‐Type Reaction Catalyzed by a Chiral Brønsted Acid

Recent Progress in Chiral Brønsted Acid Catalysis

Chiral Brønsted Acid-Catalyzed Inverse Electron-Demand Aza Diels−Alder Reaction

Chiral Brønsted Acid Catalyzed Enantioselective Hydrophosphonylation of Imines: Asymmetric Synthesis of α-Amino Phosphonates

Chiral Brønsted Acid Catalyzed Enantioselective Mannich-Type Reaction