Advances In Heterocyclic Chemistry, Vol. 60

Advances in Heterocyclic Chemistry Volume 60 Editorial Advisory Board R. A. Abramovitch, Clemson, South Carolina A. T. Balaban, Bucharest, Romania A. J. Boulton, Norwich, England H. Dorn, Berlin-Bohnsdorf, Germany J. Elguero, Madrid, Spain S. Gronowitz, Lund, Sweden E. Lukevics, Riga, Latvia 0. Meth-Cohn, Sunderland, England C. W. Rees, FRS, London, England D. StC. Black, New South Wales, Australia E. C. Taylor, Princeton, New Jersey M. TiSler, Ljubljana, Slovenia J. A. Zoltewicz, Gainesville, Florida Advances in HETEROCYCLIC CHEMISTRY Edited by ALAN R. KATRITZKY, FRS Kenan Professor of Chemistry Department of Chemistry University of Florida Gainesuille, Florida Volume 60 ACADEMIC PRESS San Diego New York Boston London Sydney Tokyo Toronto This book is printed on acid-free paper. @ Copyright 0 1994 by ACADEMIC PRESS, INC. All Rights Reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher. Academic Press, Inc. 525 B Street, Suite 1900, San Diego, California 92101-4495 United Kingdom Edition published by Academic Press Limited 24-28 Oval Road, London NWI 7DX International Standard Serial Number: 0065-2725 International Standard Book Number: 0- 12-020760-5 PRINTED IN THE UNITED STATES OF AMERICA 9 4 9 5 9 6 9 1 9 8 9 9 BB 9 8 7 6 5 4 3 2 1 Contents CONTRIBUTORS. .............................................................. PREFACE ..................................................................... vii ix Fluoro Heterocycles with Five-Membered Rings KLAUSBURGER,UWE WUCHERPFENNIG, A N D E N N OBRUNNER I . Overview.. ............................................................ 2 5 11. Direct Introduction. .................................................... 111. Introduction of Fluorine and Perfluoroalkyl Groups into Five-Membered Heterocycles via C yclocondensation Reactions .......................... 14 IV. Introduction of Fluorine, Polyfluoroalkyl, and Perfluoroalkyl Groups into Five-Membered Heterocycles via Cycloaddition Reactions . . . . . . . . . . . . . . . References. ............................................................ 28 47 Thiopyrylium, Selenopyrylium, and Telluropyrylium Salts GIANCARLO DODDIA N D GIANFRANCO ERCOLANI I. Introduction and Nomenclature .................................. 11. Structure and Physic 111. Syntheses.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV. Reactions.. ........................... V. Practical Applications .................................................. References. . . . . . . . . .................................. 66 67 99 123 I70 172 Heterocyclic Betaines: Pyridinium (Imidazolium) Azolate Inner Salts with Several Interannular Linkages ERMITASALCALDE I . Introduction.. ...................................................... 11. Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V 198 202 vi CONTENTS 111. Structure and Physical Properties ....................................... ............................................. VI. Conclusions.. .......................................................... References. ......... 222 243 250 25 1 253 Cycloaddition Reactions of Nitrile Oxides with Alkenes J . EASTON,C. MERR~CC M. HUGHES, CH