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Foreword to first edition
vii Non nova sed nove
FOREWORD to FIRST EDITION A n d t h e s e are the n a m e s . . .
The above are the opening words of Exodus, the second book of the Pentateuch. Already in ancient times, names were important in association with events. As organic chemistry developed during the 20 th century, researchers started associating synthetically useful reactions with the names of discovers or developers of these reactions. In many cases such names serve merely as a mnemonic, to remember a reaction more easily; there are few chemistry undergraduates who do not know what the FriedeI-Crafts reaction is. In recent years there has been a proliferation of new reactions and reagents that have been so useful in organic synthesis that often people refer to them by name. Many of these are stereoselective or regioselective methods. While the expert many know exactly what the Makosza vicarious nucleophilic substitution, or the Meyers asymmetric synthesis refers to, many students as well as researchers would appreciate guidance regarding such "Name Reactions". It is in this context that we perceived the necessity to incorporate the older name reactions with some newer name reactions or "unnamed reactions", that are often associated with a name but for which details, references and experimental details are not at everyone's fingertips. This was our inspiration for the current monograph "Organic Syntheses Based on Name Reactions and Unnamed Reactions".
In particular, we thought it would be useful to include cross-references of functional group transformations and an experimental procedure, so that the reader will be able to evaluate the reaction conditions at a glance; for instance, is this reaction carried out at room temperature or at 200 ~ For 1 h or 5 days? Are special catalysts required? How is the reaction worked up, what yield can be expected? The choice of which reactions to include is not an easy one. First there are the well known "Name Reactions", that have appeared in various monographs or in the old Merck index. Some of these are so obvious mechanistically to the modern organic chemistry practitioner that we have in fact omitted them; for instance, esterification of alcohols with acid c h l o r i d e s the Schbtten-Baumann procedure. Others are so important and so well entrenched by name, like the Baeyer-Villiger ketone oxidation, that it is impossible to ignore them. In general, we have kept older name reactions that are not obvious at first glance. In some cases we have combined similar reactions under one heading, for instance, the Hunsdiecker-Borodin-CristoI-Firth decarboxylative bromination. It is not a simple task to decide whether credit is due to the first discoverer of a reaction or to is developer. Often an improvement on a method is more useful than the original discovery, and usually one reaction owes its inception to some previous discovery; non nova sed nove.
viii
Organic Syntheses Based on Name Reactions
Except in the case of reactions that have been known for a long time under shared names, we often took the liberty to include in the title, as well as in the references (here to save space), only the name of the major author; for this we apologize to the co-authors, whose contributions are often seminal. For reactions named after contemporary authors, we have tried to consult the authors about choice of examples, etc. This led, for instance, to the MannichEschenmoser methylination. Among the newer reactions, we have chosen those that are not only synthetically useful, but, at first glance, not immediately obvious transformations. Another criterion was the stereochemical implication of the process. Yet, we admit our own bias in choosing from the plethora of novel transformations that have appeared in the literature over the past 30 years or so. Space limitation was by necessity a criterion. Nevertheless, we have included approximately 450 name reactions and 2100 references. We sincerely apologize if we have inadvertently omitted important reactions. In all cases we have tried to include the first reported reference, a reference to an experimental procedure, and whenever possible, a review reference (journal or Organic Reactions). In general, we did not include references to books, series of monographs, or to Organic Syntheses; chemists will of course consult these where available. Furthermore, we have compiled four indices, which should be helpful to the reader: 1. A names index with cross references to multiple names; 2. A reagents index;
3. An index to types of reactions, e.g. alkylations, stereoselective reductions, cyclizations, etc.; and 4. Most important for the synthetic chemist is an index to the synthesis of functional groups, e.g., synthesis of alkenes from ketones, as well as conversion of ketones to alkenes. We thank our families for their support and understanding during the travail on this book. Special thanks are due to my son, Lawrence Hassner, for constructive suggestions and invaluable help. We are grateful to the TEVA Pharmaceutical Co. for support of this project.
Alfred Hassner Carol Stumer
FOREWORD to FIRST EDITION A n d t h e s e are the n a m e s . . .
The above are the opening words of Exodus, the second book of the Pentateuch. Already in ancient times, names were important in association with events. As organic chemistry developed during the 20 th century, researchers started associating synthetically useful reactions with the names of discovers or developers of these reactions. In many cases such names serve merely as a mnemonic, to remember a reaction more easily; there are few chemistry undergraduates who do not know what the FriedeI-Crafts reaction is. In recent years there has been a proliferation of new reactions and reagents that have been so useful in organic synthesis that often people refer to them by name. Many of these are stereoselective or regioselective methods. While the expert many know exactly what the Makosza vicarious nucleophilic substitution, or the Meyers asymmetric synthesis refers to, many students as well as researchers would appreciate guidance regarding such "Name Reactions". It is in this context that we perceived the necessity to incorporate the older name reactions with some newer name reactions or "unnamed reactions", that are often associated with a name but for which details, references and experimental details are not at everyone's fingertips. This was our inspiration for the current monograph "Organic Syntheses Based on Name Reactions and Unnamed Reactions".
In particular, we thought it would be useful to include cross-references of functional group transformations and an experimental procedure, so that the reader will be able to evaluate the reaction conditions at a glance; for instance, is this reaction carried out at room temperature or at 200 ~ For 1 h or 5 days? Are special catalysts required? How is the reaction worked up, what yield can be expected? The choice of which reactions to include is not an easy one. First there are the well known "Name Reactions", that have appeared in various monographs or in the old Merck index. Some of these are so obvious mechanistically to the modern organic chemistry practitioner that we have in fact omitted them; for instance, esterification of alcohols with acid c h l o r i d e s the Schbtten-Baumann procedure. Others are so important and so well entrenched by name, like the Baeyer-Villiger ketone oxidation, that it is impossible to ignore them. In general, we have kept older name reactions that are not obvious at first glance. In some cases we have combined similar reactions under one heading, for instance, the Hunsdiecker-Borodin-CristoI-Firth decarboxylative bromination. It is not a simple task to decide whether credit is due to the first discoverer of a reaction or to is developer. Often an improvement on a method is more useful than the original discovery, and usually one reaction owes its inception to some previous discovery; non nova sed nove.
viii
Organic Syntheses Based on Name Reactions
Except in the case of reactions that have been known for a long time under shared names, we often took the liberty to include in the title, as well as in the references (here to save space), only the name of the major author; for this we apologize to the co-authors, whose contributions are often seminal. For reactions named after contemporary authors, we have tried to consult the authors about choice of examples, etc. This led, for instance, to the MannichEschenmoser methylination. Among the newer reactions, we have chosen those that are not only synthetically useful, but, at first glance, not immediately obvious transformations. Another criterion was the stereochemical implication of the process. Yet, we admit our own bias in choosing from the plethora of novel transformations that have appeared in the literature over the past 30 years or so. Space limitation was by necessity a criterion. Nevertheless, we have included approximately 450 name reactions and 2100 references. We sincerely apologize if we have inadvertently omitted important reactions. In all cases we have tried to include the first reported reference, a reference to an experimental procedure, and whenever possible, a review reference (journal or Organic Reactions). In general, we did not include references to books, series of monographs, or to Organic Syntheses; chemists will of course consult these where available. Furthermore, we have compiled four indices, which should be helpful to the reader: 1. A names index with cross references to multiple names; 2. A reagents index;
3. An index to types of reactions, e.g. alkylations, stereoselective reductions, cyclizations, etc.; and 4. Most important for the synthetic chemist is an index to the synthesis of functional groups, e.g., synthesis of alkenes from ketones, as well as conversion of ketones to alkenes. We thank our families for their support and understanding during the travail on this book. Special thanks are due to my son, Lawrence Hassner, for constructive suggestions and invaluable help. We are grateful to the TEVA Pharmaceutical Co. for support of this project.
Alfred Hassner Carol Stumer