Organic Reactions, Volume 2

Organic Reactions VOLUME II EDITORIAL BOARD ROGER ADAMS, Editor-in-Chief WERNER E. BACHMANN JOHN R. JOHNSON LOUIS F. FIESER H. R. SNYDER ASSOCIATE EDITORS T. A. GEISSMAN ERNEST L. JACKSON CLIFF S. HAMILTON WILLIAM S. JOHNSON ALBERT L. HENNE NATHAN KORNBLUM A. W. INGERSOLL D. STANLEY TARBELL A. L. WILDS THIRD PRINTING NEW YORK JOHN WILEY & SONS, INC. LONDON: CHAPMAN & HALL, LIMITED COPYRIGHT, 1944 BY ROGER ADAMS AU Rights Reserved This book or any part thereof must not be reproduced in any form without the wntten permission of the publisher. Third Printing, December, 1946 PRINTED IN THE UNITED STATES OP AMERICA PREFACE TO THE SERIES In the course of nearly every program ofresearch in organic chemistry the investigator finds it necessary to use several of the better-known synthetio reactions. To discover the optimum conditions for the application of even the most familiar one to a compound not previously subjected to the reaction often requires an extensive search of the literature; even then a series of experiments may be necessary. When the results of the investigation are published, the synthesis, which may have required months of work, is usually described without comment. The background of knowledge and experience gained in the literature search and experimentation is thus lost to those who subsequently have occa- sion to apply the general method. The student of preparative organic chemistry faces similar difficulties. The textbooks and laboratory man- uals furnish numerous examples of the application of various syntheses, but only rarely do they convey an accurate conception of the scope and usefulness of the processes. For many years American organic chemists have discussed these prob- lems. The plan of compiling critical discussions of the more important reactions thus was evolved. The volumes of Organic Reactions are collec- tions of about twelve chapters, each devoted to a single reaction, or a definite phase of a reaction, of wide applicability. The authors have had experience with the processes surveyed. The subjects are presented from the preparative viewpoint, and particular attention is given to limitations, interfering influences, effects of structure, and the selection of experimental techniques. Each chapter includes several detailed procedures illustrating the significant modifications of the method. Most of these procedures have been found satisfactory by the author or one of the editors, but unlike those in Organic Syntheses they have not been subjected to careful testing in two or more laboratories. When all known examples of the reaction are not mentioned in the text, tables are given to list compounds which have been prepared by or subjected to the reaction. Every effort has been made to include in the tables all such compounds and references; however, because of the very nature of the reactions discussed and their frequent use as one of the several steps of syntheses in which not all of the intermediates have been iso- lated, some instances may well have been missed. Nevertheless, the iv PREFACE TO THE SERIES investigator will be able to use the tables and their accompanying bibli- ographies in place of most or all of the literature search so often required. Because of the systematic arrangement of the material in the chapters and the entries in the tables, users of the books will be able to find information desired by reference to the table of contents of the appro- priate chapter. In the interest of economy the entries in the indices have been kept to a minimum, and, in particular, the compounds listed in the tables are not repeated in the indices. The success of this publication, which will appear periodically in volumes of about twelve chapters, depends upon the cooperation of organic chemists and their willingness to devote time and effort to the preparation of the chapters. They have manifested their interest already by the almost unanimous acceptance of invitations to con- tribute to the work. The editors will welcome their continued interest and their suggestions for improvements in Organic Reactions. CONTENTS CHAPTER ' PAGE 1. THE CLAISEN REARRANGEMENT—D. Stanley Tarbell 1 2. THE PREPARATION OP ALIPHATIC FLUOBINM COMPOVNDS—Albert L. Henne . 49 3. THE CANNIZZARO REACTION—T. A. Geissman . ... 94 4. THE FORMATION OP CYCLIC KETONES BY INTRAMOLECULAR ACYLATION— William S. Johnson ' 114 5. REDUCTION WITH ALUMINUM ALKOXIDES (THE MEERWEIN-PONNDORF- VERLEY REDUCTION)—A. L. Wilds ' 178 6. THE PREPARATION OF UNSYMMETRICAL BIARYLS BY THE DIAZO REACTION AND THE NITROSOACETYLAMINE REACTION—Werner E. Bachmann and Roger A. Hoffman 224 7. REPLACEMENT OF THE AROMATIC PRIMARY AMINO GROUP BY HYDROGEN— Nathan Kornblum 262 8. PERIODIC ACID OXIDATION—Ernest L. Jackson 341 9. THE RESOLUTION OF ALCOHOLS—A. W. Ingersoll 376 10. THE PREPARATION OF AROMATIC ARSONIC AND ARSINIC ACIDS BY THE BART, BECHAMP, AND ROSENMUND REACTIONS—Cliff S. Hamilton and Jack F. Morgan 415 INDEX 455 CHAPTER 1 THE CLAISEN REARRANGEMENT D. STANLEY TAEBBLL The University of Rochester CONTENTS PAGE INTRODUCTION 2 STRUCTURAL REQUIREMENTS FOR REARRANGEMENT; RELATED REARRANGE- MENTS • 4 SCOPE AND LIMITATIONS . ./• 6 Rearrangement in Open-Chain Compounds 6 Rearrangement of Allyl Aryl Ethers 8 The ortho Rearrangement 8 The para Rearrangement 8 Effect of Substituents in the Allyl Group 9 Effect of Substituents in the Aromatic Nucleus 11 Displacement of Substituents 11 Relation of Bond Structure to Rearrangement 13 Side Reactions 14 Mechanism of the Rearrangement 16 Synthetic Application 17 OTHER METHODS OF SYNTHESIS OF ALLYLPHENOLS 20 EXPERIMENTAL CONDITIONS AND PROCEDURES 22 Preparation of Allyl Ethers 22 Conditions of Rearrangement 0 23 Experimental-Procedures 26 Allyl Phenyl Ether 26 Allyl 2,4-Dichlorophenyl Ether *. 26 2-Allylphenol 27 2-Methyldihydrobenzofuran „ 27 Isomerization of 2-Allylphenol to 2-Propenylphenol 27 C-Alkylation. Preparation of 2-Cinnamylphenol 28 EXAMPLES OF THE REARRANGEMENT 29 Table I. Rearrangement of Open-Chain Compounds 29 A. Ethers of Enols 29 B. Rearrangements' Involving Migration to an Unsaturated Side Chain . 29 4 2 THE CLAISEN REARRANGEMENT PAGE Table II. ortho Rearrangements of Allyl Aryl Ethers 30 A. Benzene Derivatives 30 B. Polycyclic and Heterocyclic Derivatives 35 C. ortho Rearrangements with Displacement of Carbon Monoxide or Car- bon Dioxide 38 D. Rearrangements of Ethers Containing Monosubstituted Allyl Groups . 39 0-Methylallyl Ethers 39 Miscellaneous Ethers, Benzene Derivatives 40 Miscellaneous Ethers, Derivatives of Polycyclic Hydrocarbons . 42 E. Rearrangements of Ethers Containing Disubstituted Allyl Groups . 43 Table III. para Rearrangements of Allyl Aryl Ethers 44 A. Allyl Ethers of Phenols and Substituted Phenols 44 B. Ethers Containing Substituted Allyl Groups 45 C. Rearrangements Involving Displacement 47 INTRODUCTION Allyl ethers of enols and phenols undergo rearrangement to C-allyl derivatives when heated to sufficiently high temperatures. The reaction, named after its discoverer (Claisen, 1912), was first observed when ethyl O-allylacetoacetate was subjected to distillation at atmospheric pressure in the presence of ammonium chloride.1'2 OCH2CH=CHj! 0 CH2CH=CH2 CH3C=CHCO2C2HB -» CH3C—CHCO2C2HB The allyl ethers of phenols rearrange smoothly at temperatures of about 200°, in the absence of catalysts. If the ether has an unsubstituted ortho position, the product is the o-allylphenol. One of the most interesting features of the rearrangement of allyl phenyl ethers to o-allylphenols OCH2CH=CH2 OH (ortho rearrangement) is the fact that the carbon atom which becomes attached to the aromatic nucleus is not the one attached to the oxygen atom of the ether, but rather the one in the 7-position with respect to the oxygen atom (p. 9). During the rearrangement the double bond of the allyl group shifts from the /3,7-position to the a,/3-position. T.he inversion of the allyl group is apparent, of course, only when substituents are present on either the a- or 7-carbon atom. Crotyl phenyl ether (I), for example, rearranges to the branched-chain o-methylallylphenol (II). 1 Claisen, Ber., 45, 3157 (1912). 8 Claisen, BeHstein, Supplementary Volume III-IV, p. 256. INTRODUCTION a 0 y OCH2C&=CHCH3 OH y $ a —CHCH==CH, CHs Allyl ethers of ortfto-disubstituted phenols rearrange to the correspond- ing p-allylphenols. It is noteworthy that the para rearrangement is not usually accompanied by inversion of the allyl group.3-4-6- 6>7 For example, cinnamyl 2-carbomethoxy-6-methylphenyl ether (III) rearranges without inversion3 to yield the p-cinnamyl derivative (IV). OCH2CH=CHC6HB OH CH2CH=CHC6H5 in iv The crotyl ether of the same phenol also rearranges without inversion.8 The only known example of para rearrangement accompanied by inversion is the reaction of a-ethylallyl 2-carbomethoxy-6b-methy]phenyl ether (V), which yields the p-(7-ethylallyl) derivative (VI).6 OCH(C2HB)CH=CH2 CH2CH=CHC2H6 v vi This is also the only known example of para rearrangement in which a substituent is present on the a-carbon atom of the allyl group in the ether. Although the number of known para rearrangements in which inversion or non-inversion can be detected hardly justifies a generaliza- tion, it does appear that a substituent on the 7-carbon atom of the allyl group prevents inversion, whereas a substituent qn the a-carbon atom favors inversion. In other werds, the para rearrangement appears to operate in such a way that either an a- or 7-substituted allyl group leads to a straight-chain substituent in the product. The occurrence of inversion in the rearrangement of enol ethers appears to be dependent upon, the experimental conditions, at least in some instances. This question is discussed on p. 7. * Mumm and Moller, Ber., 70, 2214 (1937). 4 Sp&th and Holzer, Ber., 66, 1137 (1933). 8 SpSth and Kuffner, Ber., 72, 1580 (1939). ' Mumm, Hornhardt, and Diederichsen, Ber., 72, 100 (1939). 7 Mumm and Diederichsen, Ber., 72, 1523 (1939).

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