Preface. See for options on how to legitimately share published articles.

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1 Preface Downloaded via on July 7, 2018 at 21:02:33 (UTC). See for options on how to legitimately share published articles. The synthesis of new chiral organic compounds and the improved synthesis of known substances will always be a major task for the professional chemist. When constructing target molecules with multiple chirality centers, a scientist must consider either total synthesis step by step or assembly from smaller chiral blocks as an alternative approach. Carbohydrates represent a unique family of polyfunctional compounds, which can be chemically or enzymatically manipulated in a multitude of ways. Carbohydrates have been extensively used as starting materials in enantioselective synthesis of many, complex natural products with multiple chirality centers. Synthetic organic chemistry that utilizes these carbohydrate building blocks continues to spawn revolutionary discoveries in medicinal chemistry, pharmacology, molecular biology, glycobiology, and medicine simply by providing not only the raw material but also the mechanistic insight of modem molecular sciences. This interdisciplinary approach to modem discoveries and many further innovations continue to drive the core of synthetic carbohydrate chemistry. The environmentally and ecologically friendly nature of carbohydrates is also a cornerstone in their future developments in the polymer and pharmaceutical industries and in the area of carbohydrate therapeutics in particular. Corey (E.J Corey Pure Appl Chem 1969, 14, 30) introduced the term synthon in 1969 when he published his innovative strategies for the construction of complex molecules by considering a retrosynthetic analysis. Later on, Hanessian's (Total Synthesis of Natural Products: The 'Chiron' Approach; Pergamon Press, 1983) introduction in 1983 of the term Chiron reférring to chiral synthons became the general strategy of carbohydrate like symmetry in new molecular targets of many natural products. Despite the greater awareness of carbohydrate synthons in recent years, the full potential of the carbohydrate chiral pool is still not ix

2 fully used. Thus, this fact gives enormous rationale in organizing our symposium and presenting new developments by a team of world-class scientists. Consequently, publishing this symposium proceeding will assist the carbohydrate community in keeping abreast of new innovations. We hope that these few, important forward-looking topics of brand new developments from world-class leading laboratories will effectively fill the gap of previously unavailable practical information regarding the unlimited possibility of applying carbohydrate building blocks. Among a few often-used carbohydrate building blocks, L- arabinose is one of the most important and easily commercially available monosaccharides. Next, in terms of availability and potential functionality are naturally protected 1,6-anhydrosugars derivatives such as levoglucosan and levoglucosenone. Both compounds possess enormous potential for becoming new stars among industrial chemicals, simply because of their multiple usage in many areas of industry (including polymer chemistry, biotechnology, pharmaceutical intermediates, and carbohydrate scaffolds for combinatorial chemistry approaches). Industrial production of these convenient chiral building blocks from waste cellulosic material, such as newsprint or any waste paper, could solve some environmental problems and could be classified as green chemistry. The raw carbohydrate material for the functionalization into useful building blocks must be economically feasible and cost effective; waste cellulosic materials fit into that category very well. Particularly valuable building blocks such as levoglucosenone, isolevoglucosenone, L-arabinose, parasorbic acid, dihydropyranones, 3-hy droxy-γ-butyro-lactones, 1 -thio-1,2-o-isopropylidene acetals, ω-bromo-α-β unsaturated aldonolactones, bicyclic furanones, arabinonic acid γ-lac-one and glycosyl isocyanides are explored for their synthetic applicability in many synthetic targets of natural products of medicinal interest. Most of the chapters in this book were presented in the special symposium Chemistry for the 21st Century at the 218 th ACS National Meeting in San Francisco, California on March 26-30, Other chapters, not presented at the symposium, are contributions from leading scientists in the field of carbohydrate chemistry. x

3 Most importantly, these topics will help steer the future of new developments in this area and will help promote the enormous potential of many innovations among almost all chemical industries in the new millennium. This is not a simple goal, but a 21st century challenge to educate the industrial leaders, public, and governmental funding agencies about the enormous potential and usefulness of these traditional and new carbohydrate synthons as chemicals for the 21st century. Acknowledgment We thank all the authors for their excellent contributions to this volume. We also thank the peer reviewers of the chapters for their expertise and enormous efforts to improve the quality of the manuscripts. We are grateful to the ACS Division of Carbohydrate Chemistry for sponsoring the symposium upon which this book is based. We also acknowledge Kelly Dennis and Stacy VanDerWall in acquisitions and Margaret Brown in editing/production of the ACS Books Department for their help in coordinating and producing the book. We dedicate this book to our wives Wanda and Yoko. Zbigniew J. Witczak Department of Pharmaceutical Sciences Nesbitt School of Pharmacy. Wilkes University Wilkes-Barre, PA Kuniaki Tatsuta Graduate School of Science and Engineering Waseda University Shinjuku Tokyo , Japan xi

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5 Carbohydrate Synthons in Natural Products Chemistry