Asymmetric Bronsted Acid Catalysis

A much-needed overview of the synthesis of chiral Brønsted acids and their applications in various organic transformations. The internationally recognized and highly respected expert authors summarize the most significant advances in this new and dynamically progressing field, with a special emphasis on BINOL-derived phosphoric acids. They also describe other catalysts, such as C-H, TADDOL-derived Brønsted, and sulfonic acids. For easy navigation, the chapters are organized in the first instance according to reactive intermediate and then sub-divided by reaction type. An appendix with selected experimental details for benign and straight-forward procedures rounds of the book, making this the number-one information source for organic chemists in academia and industry.

Table of Contents:
Preface IX 1 Introduction 1 1.1 Book Structure and Notation 1 1.2 Catalyst Preparation 2 1.3 Metal Impurities 3 References 3 2 Reactions of Imines 5 2.1 Nucleophilic Addition Reactions 5 2.1.1 C-Nucleophiles 5 2.1.2 N-Nucleophiles 17 2.1.3 O-Nucleophiles 20 2.1.4 P-Nucleophiles 21 2.2 Mannich Reactions 24 2.3 Strecker Reactions 28 2.4 Biginelli Reactions 31 2.5 Friedel–Crafts Reactions 33 2.5.1 Indole Coupling Partners with Aldimines 33 2.5.2 Indole Coupling Partners to Ketimines 35 2.5.3 Non-Indole Aromatic Partners 38 2.5.4 Pictet–Spengler Reactions 41 2.6 Transfer Hydrogenations 44 2.6.1 Imine Partners 44 2.6.2 α-Imino Ester Partners 49 2.6.3 N-Heterocycles 51 2.6.4 Cascade Processes 56 2.6.5 Miscellaneous Reactions 61 2.7 Pericyclic Reactions 63 2.7.1 Aza-Diels–Alder/Povarov 63 2.7.2 1,3-Dipolar Cycloaddition 69 2.7.3 Electrocyclizations and Sigmatropic Rearrangements 72 2.8 Radical Reactions 77 References 79 3 Reactions of Generated Imine Intermediates 87 3.1 Enamines 87 3.1.1 Nucleophilic Addition Reactions 87 3.1.2 Transfer Hydrogenation 90 3.2 Indoles Containing Leaving Groups 91 3.2.1 Nucleophilic Addition Reactions 92 3.2.2 Friedel–Crafts Reactions 96 3.3 N-Acetals and Aminals 99 3.3.1 Nucleophilic Addition Reactions 99 3.3.2 Friedel–Crafts Reactions 104 3.3.3 Transfer Hydrogenation 105 3.4 Miscellaneous Formation 111 References 115 4 Reactions of Carbonyls 117 4.1 Nucleophilic Addition Reactions 117 4.1.1 C-Nucleophiles 117 4.1.2 N-, O-, and P-Nucleophiles 124 4.2 Aldol Reactions 133 4.3 Pericyclic Reactions 137 4.4 Reductions 140 References 142 5 Reactions of Generated Carbonyl Intermediates 145 5.1 Enol Ethers 145 5.2 Acetals 149 5.3 Phenols Containing Leaving Groups 153 References 158 6 Reactions of Alkenes 161 6.1 Nucleophilic Addition Reactions 161 6.2 Friedel–Crafts Reactions 169 6.3 Pericyclic Reactions 172 6.4 Cascades 177 References 180 7 Reactions of Other Substrates 183 7.1 Aziridines 183 7.2 O-Heterocycles and Ethers 185 7.3 Hydrazines and Hydrazones 190 7.4 Azo/Diazo Substrates 192 7.5 Halogens 198 7.5.1 Fluorine 198 7.5.2 Bromine 203 7.6 Oxidizing Agents 206 7.7 Miscellaneous Substrates 209 References 212 Experimental Protocols 215 Appendix A: Catalyst Frequency 215 Appendix B: Overview of Phosphoric Acids (PA) 217 Appendix C: Overview of N-Phosphoramide Acids (NPA) 221 Appendix D: Overview of SPINOL Phosphoric Acids (SPA) 223 Appendix E: Overview of All Other Brønsted Acids (BA) 225 Index 229

About the Author :
Magnus Rueping is Professor of Organic Chemistry at RWTH Aachen University, Germany. He studied at the Technical University of Berlin, Trinity College Dublin, and ETH Zürich, where he completed his diploma thesis under the direction of Prof. D. Seebach. He stayed in the Seebach group and obtained his Ph.D. from the ETH in 2002. He then moved to Harvard University to work with Prof. D. Evans on enantioselective transition-metal catalysis. In August 2004, he was directly appointed to a C3-professorship, the Degussa Endowed Professorship of Synthetic Organic Chemistry at Goethe University Frankfurt. In 2008 he accepted a Chair and Full Professorship of Organic Chemistry at RWTH Aachen University. His group's current research interests include enantioselective organocatalysis, metal- and biocatalysis, new reaction methodology and technology, new materials as well as photochemistry and flow chemistry. Dixit Parmar is an Alexander von Humboldt fellow at RWTH Aachen University, Germany. He obtained his MChem degree in Chemistry with first class honours from the University of Manchester, UK, in 2008. He stayed there further to conduct his Ph.D. with Prof. D. Procter on the development of reductive lactone cyclization cascades mediated by SmI2-H2O. In 2012, he moved to RWTH Aachen University as a postdoctoral researcher in the group of Prof. M. Rueping. His research interests include organocatalysis and asymmetric fluoro-cyclizations. He has received the prestigious Reaxys PhD Prize in 2011. Erli Sugiono is a senior scientist at RWTH Aachen University, Germany. She graduated from the Johannes Gutenberg University of Mainz, Germany, and obtained her Ph.D. in the research group of Prof. H. Meier. She then joined the Max-Planck-Institute of Polymer Research (Mainz) as a postdoctoral fellow in the group of Prof. Dr. H.W. Spiess. She joined the group of Prof. M. Rueping in 2005 and was appointed to the position of senior scientist in 2009. Her work centers on the development of new methodologies for asymmetric catalytic transformations, catalytic flow reactions and the synthesis of biologically active compounds.