Sodium triacetoxyborohydride is presented as a general reducing agent for the reductive amination of aldehydes and ketones. Procedures for using this mild and selective reagent have been developed for a wide variety of substrates. The scope of the reaction includes aliphatic acyclic and cyclic ketones, aliphatic and aromatic aldehydes, and primary and secondary amines including a variety of weakly basic and nonbasic amines. Limitations include reactions with aromatic and unsaturated ketones and some sterically hindered ketones and amines. 1,2-Dichloroethane (DCE) is the preferred reaction solvent, but reactions can also be carried out in tetrahydrofuran (THF) and occasionally in acetonitrile. Acetic acid may be used as catalyst with ketone reactions, but it is generally not needed with aldehydes. The procedure is carried out effectively in the presence of acid sensitive functional groups such as acetals and ketals; it can also be carried out in the presence of reducible functional groups such as C−C multi...

Reductive Amination of Aldehydes and Ketones with Sodium Triacetoxyborohydride. Studies on Direct and Indirect Reductive Amination Procedures1

Chiral nitrogen-containing compounds are widely distributed in nature and include many biologically important molecules (Chart 1). In these compounds, the nitrogen-containing units are known to play important roles for their bioactivities. For the synthesis of these chiral nitrogen-containing building blocks, use of imines as electrophiles is the most promising and convenient route.1 While many approaches using chiral imines or chiral nucleophiles have been reported,1 these diastereoselective reactions have some disadvantages. First, the procedures to introduce chiral auxiliaries to substrates and to remove them after the diastereoselective reactions are often tedious. Second, more than stoichiometric amounts of chiral sources are needed to obtain chiral compounds according to these reactions. On the other hand, catalytic enantioselective reactions provide the most efficient methods for the synthesis of chiral compounds,2 because large quantities of chiral compounds are expected to be prepared using small amounts of chiral sources. While much progress has been made recently in catalytic enantioselective reactions of aldehydes and ketones such as aldol,3 allylation,4 Diels-Alder,5 cyanation reactions,6 reduction,1b,2b etc., progress in catalytic enantioselective reactions of imines is rather slow. There are some difficulties in performing catalytic enantioselective reactions of imines. For example, in the cases of chiral Lewis acid promoted asymmetric Shū Kobayashi was born in 1959 in Tokyo, Japan. He studied chemistry at the University of Tokyo and received his Ph.D. in 1988 (Professor T. Mukaiyama). After spending 11 years at Science University of Tokyo (SUT), he moved to Graduate School of Pharmaceutical Sciences, University of Tokyo, in 1998. His research interests include development of new synthetic methods, development of novel catalysts (especially chiral catalysts), organic synthesis in water, solid-phase organic synthesis, total synthesis of biologically interesting compounds, and organometallic chemistry. He received the first Springer Award in Organometallic Chemistry in 1997.

https://chemistry.mdma.ch/hiveboard/picproxie_docs/000499541-cr980414z.pdf

Catalytic enantioselective addition to imines.

Targeted delivery combined with controlled drug release has a pivotal role in the future of personalized medicine. This review covers the principles, advantages, and drawbacks of passive and active targeting based on various polymer and magnetic iron oxide nanoparticle carriers with drug attached by both covalent and noncovalent pathways. Attention is devoted to the tailored conjugation of targeting ligands (e.g., enzymes, antibodies, peptides) to drug carrier systems. Similarly, the approaches toward controlled drug release are discussed. Various polymer–drug conjugates based, for example, on polyethylene glycol (PEG), N-(2-hydroxypropyl)methacrylamide (HPMA), polymeric micelles, and nanoparticle carriers are explored with respect to absorption, distribution, metabolism, and excretion (ADME scheme) of administrated drug. Design and structure of superparamagnetic iron oxide nanoparticles (SPION) and condensed magnetic clusters are classified according to the mechanism of noncovalent drug loading involving...

Targeted Drug Delivery with Polymers and Magnetic Nanoparticles: Covalent and Noncovalent Approaches, Release Control, and Clinical Studies.

BINOL: A Versatile Chiral Reagent

Contents 1.0Introduction
1.1 Polystyrene Supports as Carriers for Reagents and Catalysts
1.2 Catalyst and Reagent Attachment to Polymer Supports
2.0C-C Bond Formation Using Recyclable Resin-Based Reagents and Catalysts
2.1 Palladium-Catalyzed Coupling Reactions
2.2 Other Transition Metal Catalyzed Reactions
2.3 Resin-Supported Olefin Metathesis
2.4 Resin-Mediated Cycloaddition Reactions
2.4.1 Diels-Alder Cycloadditions
2.4.2 Resin-Based Catalysts for 1,3-Dipolar Cycloadditions
2.5 Immobilized Chiral Ligands for Diethylzinc Additions to Aldehydes
2.6 Miscellaneous: Other C-C Bond Forming Reactions
3.0Immobilized Oxidants
3.1Oxidation with Immobilized Transition Metal Complexes
3.2 Alcohol Oxidation
3.3 Alkene Oxidation
3.3.1 Dihydroxylation
3.3.2 Epoxidation
3.3.3 Asymmetric Epoxidation
3.3.4 Other Alkene Oxidation Reactions
3.4 Potpourri: Other Immobilized Oxidants
4.0Immobilized Resin-Based Reductants
4.1 General Reduction Processes
4.2 Asymmetric Reduction of Ketones
4.3 Alkene Reduction
4.4 Resin-Based Tin and Germanium Reductants
5.0Conclusions
6.0Abbreviations
7.0Acknowledgments
8.0References

Recoverable Catalysts and Reagents Using Recyclable Polystyrene-Based Supports

Selective deoxygenation of ketones and aldehydes including hindered systems with sodium cyanoborohydride

Nucleophilic borohydride: selective reductive displacement of halides, sulfonate esters, tertiary amines, and N,N-disulfonimides with borohydride reagents in polar aprotic solvents

Cyanoborohydride. utility and applications in organic synthesis. a review

La reduction de cyclohexyl-imines, sels d'iminium et enamines substitues en −2 et −4 par divers hydrures montre que des reactifs du type NaBH 4 ou NaBH 3 CN favorisent une approche axiale, alors que des reactifs moderement encombres (par exemple des acetoxyluranes) attaquent preferentiellement du cote equatorial

Robert O. Hutchins

Papers

Selective deoxygenation of ketones and aldehydes including hindered systems with sodium cyanoborohydride

Nucleophilic borohydride: selective reductive displacement of halides, sulfonate esters, tertiary amines, and N,N-disulfonimides with borohydride reagents in polar aprotic solvents

Cyanoborohydride. utility and applications in organic synthesis. a review

Stereoselective reductions of substituted cyclohexyl and cyclopentyl carbon-nitrogen .pi. systems with hydride reagents

Selective reductive displacement of alkyl halides and sulfonate esters with cyanoborohydride reagents in hexamethylphosphoramide