Studies in Natural Products Chemistry (eBook)

Front Cover 1
Stereoselective Synthesis (Part H) 4
Copyright Page 5
Table of Contents 10
FOREWORD 6
PREFACE 8
CONTRIBUTORS 12
PART 1: Stereoselective Synthesis 14
Chapter 1. Synthetic Routes to the Oxahydrindene Subunit of the Avermectin- Milbemycin Family of Antiparasitic Agents: A Review 16
1. Introduction: Isolation, Structure Elucidation, Biosynthesis, and Biological Activity of the Avermectins 16
2. Synthetic Routes to the Oxahydrindene Subunit of the Avermectins 22
Acknowledgments. 44
References 44
Chapter 2. A New Tandem Process and its Application to the Synthesis of Macrolide Antibiotics 48
1. Introduction 48
2. A new tandem process (Two-stage coupling process) 48
3. Synthesis of the rifamycin S ansa-chain compound 50
4. Synthesis of the rifamycin W ansa-chain compound 52
5. Total synthesis of rifamycin W 59
6. Total synthesis of erythronolide A 61
7. Total synthesis of erythromycin A 66
8. Mechanistic considerations about the diastereoselective first step (Stage I) of the new tandem process 68
References 72
Chapter 3. Stereoselective Synthetic and Mechanistic Chemistry of Bicyclomycin 76
INTRODUCTION 76
ISOLATION, STRUCTURAL ELUCIDATION AND BIOSYNTHESIS 77
MECHANISM OF ACTION 108
CONCLUDING REMARKS 122
REFERENCES AND FOOTNOTES 123
Chapter 4. The Role of Isocyanides in the Synthesis of ß-Lactam Antibiotics and Related Compounds 126
1. INTRODUCTION 126
2. ß-LACTAM ANTIBIOTICS 131
3. MODIFICATIONS OF ß-LACTAM ANTIBIOTICS THROUGH ISOCYANIDE CHEMISTRY 146
4. PERSPECTIVES 151
REFERENCES 153
Chapter 5. Synthesis of the lß-Methylcarbapenem Key Intermediates Yoshio Ito and Shiro Terashima 158
1. Introduction 158
2. Construction of the Carbapenem Framework 159
3. Synthesis of Key lß-Methylcarbapenem Intermediates 161
References 188
Chapter 6. Chemical Studies of the Taxane Diterpenes Charles S. Swindell 192
1. INTRODUCTION 192
2. TOTAL SYNTHESIS 194
3. THE DEVELOPMENT OF AN A-RING ANNULATION STRATEGY FOR TAXANE SYNTHESIS 216
4. PARTIAL SYNTHESIS OF TAXOL AND ITS STRUCTURE-AOTVITY PROFILE 230
5. BIOLOGICALLY ACTIVE TAXOL ANALOGUES WITH DELETED Á-RING SIDECHAIN SUBSTITUENTS AND VARIABLE C-2' CONFIGURATIONS 234
ACKNOWLEDGMENT. 240
REFERENCES 240
Chapter 7. Recent Advances in the synthesis of Tumor-Promoting Diterpenes 246
1. INTRODUCTION 246
2. INGENANE SYNTHETIC STUDIES 247
3. PHORBOL SYNTHETIC STUDIES 258
REFERENCES 285
Chapter 8. Hydroxylated Indolizidines and their Synthesis 288
1. Introduction 288
2. The 1-hydroxyindolizidines (octahydroindolizin-l-ols) 291
3. The 2-hydroxyindoIizidines (octahydroindolizin-2-ols) 296
4. The 5-hydroxy-4-oxyindolizidines 297
5. The 6-hydroxyindolizidines (octahydroindo!izin-6-oIs) 298
6. The 7-hydroxyindoIizidines (octahydroindolizin-7-oIs) 299
7. Elaeokanine C 302
8. The 8-hydroxyindoIizidines (octahydroindolizin-8-oIs) 306
9. The pumiliotoxins 307
10. The allopumiliotoxins 310
11. The 8a-hydroxyindoIizidines (octahydroindolizin-8a-oIs) 313
12. The 1,2-dihydroxyindoIizidines (octahydroindoIizin-l,2-dioIs) 316
13. Slaframine 319
14. Swainsonine 326
15. Swainsonine stereomers 338
16. Castanospermine 345
17. Castanospermine stereomers and analogues 355
REFERENCES 368
Chapter 9. A Survey of Indolo [2,3-a] carbazole Alkaloids and Related Natural Products 378
1. INTRODUCTION 378
2. OCCURRENCE 378
3. BIOGENESIS 386
4. SYNTHESIS 388
5. BIOLOGICAL ACTIVITY 397
6. CONCLUDING REMARKS 412
ACKNOWLEDGEMENT 415
REFERENCES 415
Chapter 10. Synthetic Methodology for 2-Amino Alcohols of Biological Interest 424
1. INTRODUCTION 424
2. CHIRAL SYNTHONS FOR 2-AMINO ALCOHOLS 429
3. CONVERSION PROCESSES TO 2-AMINO ALCOHOLS 438
4. SYNTHETIC APPLICATIONS TO HYDROXY AMINO ACIDS 444
5. Conclusion 451
References and Notes 452
Chapter 11. Stereoselective Synthesis of Natural Products via Cationicand Radical Intermediates 458
1. INTRODUCTION 458
2. INTRAMOLECULAR ARYLATION OF N-ACYLIMINIUM IONS 460
3. N-ACYLIMINIUM ION-VINYLSILANE CYCLIZATION IN THE SYNTHESIS OF 466
4. N-ACYCLIM1NIUM ION INITIATED POLYENE CYCLIZATION 469
5. á-ACYLAMINO RADICAL CYCLIZATION IN A SYNTHESIS OF PYRROLIDINE AND PIPERIDINE DERIVATIVES 484
6. STEREOSELECTIVE SYNTHESIS OF ß-OXYGENATED .-AMINO ACIDS 489
REFERENCES 506
SUBJECT INDEX 512