By Irishi N. N. Namboothiri, Meeta Bhati, Madhu Ganesh, Basavaprabhu Hosamani, Thekke V. Baiju, Shimi Manchery, and Kalisankar Bera
Contents
Foreword…………………………………………………………………………………. xiii
Preface…………………………………………………………………..xv
Authors ……………………………………………………………………xvii
Introduction…………………………………………………………………1
Chapter 1 Catalytic Asymmetric Michael Addition of 1,3-Dicarbonyls to Nitroalkenes …………7
1.1 I ntroduction ………………………………………………………………………………………….7
1.2 Addition of 1,3-Diketones ………………………………………………………………………7
1.3 Addition of Malonates………………………………………………………………………….. 14
1.4 Addition of β-Ketoesters ………………………………………………………………………26
1.5 Addition of 2-Hydroxynaphthoquinones ………………………………………………… 33
1.6 Addition of Hydroxycoumarin ……………………………………………………………… 35
1.7 Addition of Meldrum’s Acid…………………………………………………………………..37
1.8 Conclusions …………………………………………………………………………………………39
References ……………………………………………………………………………………………………39
Chapter 2 Catalytic Asymmetric Michael Addition of Aldehydes to Nitroalkenes ………………. 43
2.1 Introduction ……………………………………………………………………………………….. 43
2.2 Addition of Aldehyde Enolates ……………………………………………………………… 43
2.3 Addition of Umpolung of Aldehydes: The Stetter Reaction ………………………. 71
2.4 Conclusions …………………………………………………………………………………………73
References…………………………………………………………………………………………………….73
Chapter 3 Catalytic Asymmetric Michael Addition of Ketones to Nitroalkenes……………………77
3.1 I ntroduction ………………………………………………………………………………………..77
3.2 Addition of Aliphatic and Aromatic Ketones……………………………………………77
3.3 Addition of α-Ketoesters, α-Ketoamides and α-Ketophosphonates…………… 107
3.4 Addition of β-Ketosulfones ………………………………………………………………… 111
3.5 Conclusions……………………………………………………………………………………….. 112
References …………………………………………………………………………………………………. 112
Chapter 4 Catalytic Asymmetric Michael Addition of Miscellaneous Carbonyl
Compounds to Nitroalkenes …………………………………………………………………………. 115
4.1 I ntroduction………………………………………………………………………………………. 115
4.2 Addition of Esters/Lactones: Iminoesters, Furanones,
Oxazolones and Isoxazolones 115
4.3 Addition of Amides/Lactams: Oxindoles, Pyrazolones and Pyrrolidones … 122
4.4 Conclusions ………………………………………………………………………………………. 134
References …………………………………………………………………………………………………. 134
Chapter 5 Catalytic Asymmetric Friedel–Crafts Reactions of Nitroalkenes………………………. 137
5.1 Introduction ……………………………………………………………………………………… 137
5.2 Friedel–Crafts Reaction …………………………………………………………………….. 137
5.3 Conclusions ………………………………………………………………………………………. 158
References …………………………………………………………………………………………………. 158
Chapter 6 Catalytic Asymmetric Michael Addition of Miscellaneous Carbon-centered
Nucleophiles to Nitroalkenes ……………………………………………………………………….. 161
6.1 I ntroduction ……………………………………………………………………………………… 161
6.2 Addition of Nitroalkanes…………………………………………………………………….. 161
6.3 Addition of Cyanides………………………………………………………………………….. 166
6.4 Addition of Boronic Acids…………………………………………………………………… 168
6.5 Addition of Malononitrile……………………………………………………………………. 172
6.6 Addition of Organo-Zinc Reagents ……………………………………………………… 174
6.7 Conclusions ………………………………………………………………………………………. 180
References …………………………………………………………………………………………………. 180
Chapter 7 Catalytic Asymmetric Michael Addition of Heteroatom-centered
Nucleophiles to Nitroalkenes ……………………………………………………………………….. 183
7.1 I ntroduction ……………………………………………………………………………………… 183
7.2 Addition of Phosphorus-centered Nucleophiles …………………………………….. 183
7.3 Addition of Sulphur-centered Nucleophiles ………………………………………….. 188
7.4 Addition of Nitrogen-centered Nucleophiles………………………………………….. 192
7.5 Addition of Oxygen-centered Nucleophiles ………………………………………….. 195
7.6 A ddition of Arsenic-centered Nucleophiles ………………………………………….. 197
7.7 C onclusions ………………………………………………………………………………………. 198
References …………………………………………………………………………………………………. 198
Chapter 8 Catalytic Asymmetric Cycloadditions of Nitroalkenes ……………………………………. 201
8.1 I ntroduction ……………………………………………………………………………………… 201
8.2 [3+2] Cycloadditions…………………………………………………………………………… 201
8.3 [4+2] Cycloadditions ………………………………………………………………………….. 215
8.4 Other Cycloadditions………………………………………………………………………….. 221
8.5 C onclusions ……………………………………………………………………………………….223
References ………………………………………………………………………………………………….223
Chapter 9 Catalytic Asymmetric Reduction of Nitroalkenes…………………………………………….227
9.1 I ntroduction……………………………………………………………………………………….227
9.2 Metal Catalyzed Reduction………………………………………………………………….227
9.3 Organocatalyzed Reduction………………………………………………………………… 232
9.4 Bioreduction …………………………………………………………………………………….. 233
9.5 Conclusions ………………………………………………………………………………………. 235
References …………………………………………………………………………………………………. 235
Chapter 10 Catalytic Asymmetric Synthesis of Cycloalkanes via Cascade
Reactions of Nitroalkenes ……………………………………………………………………………. 237
10.1 Introduction………………………………………………………………………………………. 237
10.2 Synthesis of Cycloalkanes…………………………………………………………………… 237
10.3 Conclusions……………………………………………………………………………………….. 253
References ………………………………………………………………………………………………….254
Chapter 11 Catalytic Asymmetric Synthesis of Aryl-Fused Heterocycles via Cascade
Reactions of Nitroalkenes ……………………………………………………………………………. 257
11.1 I ntroduction………………………………………………………………………………………. 257
11.2 Synthesis of Aryl-Fused Heterocycles………………………………………………….. 257
11.3 C onclusions……………………………………………………………………………………….. 273
References………………………………………………………………………………………………….. 273
Chapter 12 Catalytic Asymmetric Synthesis of Five- and Six-Membered Heterocycles via
Cascade Reactions of Nitroalkenes ……………………………………………………………….. 275
12.1 Introduction………………………………………………………………………………………. 275
12.2 Synthesis of Five- and Six-Membered Nitrogen Heterocycles …………………. 275
12.3 Synthesis of Five- and Six-Membered Oxygen Heterocycles…………………… 278
12.4 Synthesis of Spiro-Oxindoles……………………………………………………………….287
12.5 Conclusions …………………………………………………………………..293
References …………………………………………………………….293
Index …………………………………………………295
Preface
Conjugated nitroalkenes are versatile substrates in organic synthesis because of their ability to par-ticipate in a wide variety of reactions, including multicomponent and cascade reactions, primarily due to the strong electron-withdrawing and coordinating ability of the nitro group. The easy acces-sibility of nitroalkenes and the amenability of the nitro group to undergo diverse synthetic transfor-mations have further strengthened the profile of nitroalkenes as promising substrates in both regio and stereoselective synthesis of complex designed molecules and natural products. These unique features of nitroalkenes have prompted synthetic organic chemists to employ nitroalkenes as sub-strates in catalytic asymmetric reactions. Over the past two decades, numerous chiral metal-based and organocatalysts have been employed in various asymmetric reactions involving nitroalkenes not only toward developing new methodologies but in targeted synthesis as well.
Over 25 reviews have appeared in the literature since 2002 on various catalytic asymmetric reactions of nitroalkenes. However, while those excellent reviews have highlighted different facets of nitroalkenes, a comprehensive coverage of the multifaceted reactivity of nitroalkenes in cata-lytic asymmetric reactions was probably beyond the scope of a journal review or a book chapter. Therefore, we felt that synthetic organic chemists and medicinal chemists interested in nitroalkene-derived enantioenriched molecules with key functional groups and potential bioactivity would ben-efit if a systematic compilation of various asymmetric synthetic methods involving nitroalkenes as substrates in the presence of various chiral catalysts developed till date is available in one place. New insights into the mechanistic aspects and stereoselectivity could be of interest to physical organic chemists as well as theoretical chemists.
This book begins with a brief introduction to the catalytic asymmetric reactions of nitroalkenes with reference to the journal reviews and the book chapters that have appeared in the literature thus far. This is followed by a chapter-wise description of the reactivity of nitroalkenes in Michael addition, cycloadditions and cascade reactions (see Introduction). We have made every effort to include all the reagents and reaction conditions in the schemes. Further, the number of examples, product yield, diastereomeric ratios and enantiomeric excess have also been included. Although the mechanism is discussed in the text in most cases, the detailed mechanistic schemes are included only in selected cases. However, all available transition state models are presented and discussed to rationalize the observed stereoselectivity. Over 650 articles, including reviews, have been covered in this book. But if there are any omissions, we apologize in advance and promise to include them in the next edition.
We are deeply grateful to Prof Takemoto who is a pioneer in the arena of asymmetric catalysis for writing a foreword to this book. We are highly indebted to Prof Viswakarma Singh for patiently and critically reading all the chapters and giving his valuable suggestions and comments. We sincerely thank our group members Pallabita Basu, Sonia Naik and Nikil Purushotham for proofreading the manuscript. We also thank the editor Dr Renu Upadhyay and her associate Ms Jyotsna Jangra for their guidance and support. Finally, INN thanks his wife Jayasree and daughters Ashcharya and Susmrithi for allowing him to spend extended hours in his office to complete this book.