Chemical Reviews Volume 88. Number 8 December 1988 The Thermal, Aliphatic Claisen Rearrangement FREDERICK E. ZIEGLER steriing Ctmm!.qtry Labaatory. Yale UnivennV, New Haven. Connecticur 08511-8118 Receh.ed April 25. 1988 (Revised Manusnipt Received Seplember 8. 1988) Contents I. Introduction 11. Historical Overview 111. Mechanistic Aspects A. Kinetics B. Retro-Clalsen Rearrangement C. Competitive Rearrangements 1. [3.3] Claisen vs [2,3] Wmig 2. Diinylcarbinol Derivatives 3. Elimination D. Stereochemistry 1. Transition State 2. Vinyl Double-Bond Geometry 3. Secondary Allylic Alcohols 4. Tertiary Allylic Alcohols 5. RingBearing Substrates Rearrangement IV. Heteroatom Substituents A. The Vinyl Group 1. C, Hetero Substituents 2. C, Carbon Hetero Substituents 1. Oxygen Substituents Silicon Substituents Allylic Group V. Remote Asymmetry A. Acyclic Substrates Ring-Bearing Substrates VI. Consecutive Rearrangements A. Sequential Rearrangements 8. Tandem Rearrangements C. Iterative Rearrangements A. (1,llRearrangements (1.2JRearrangements C. (1.41-Rearrangements (1.5lRearrangements E. (1.61-Rearrangements F. (2.41-Rearrangements G. (4.5l-Rearrangements H. (4.61-Rearrangements I. (5.61-Rearrangements VII. Synthetic Applications VIII. Biochemical Aspects IX. Concluding Remarks 1423 1424 1425 1427 1428 1429 1431 1433 1433 1435 1436 1437 1438 1440 1441 1442 1443 1444 1445 1446 1448 A. Frederick E. Ziegier received his B.S. from Fairiegh Dickinson University in 1960 and Ph.D. in 1964 from Columbia University where he studied under Gilbert Stork. As an NSF postdoctoral student. he spent 1 year in the laboratory of George Buchi at Massachusetts Institute of Technology. He joined the Yale Univ- ersity facuHy in 1965 where he currently hokk the rank Professor Chemistry. His research interests include the synthesis of physiologically active natural products, study of stereo- chemistry aganic reactions. and the development of new syn- thetic methods. I. Introduction This past year the diamond annivenary of the pub- lication of Ludwig Claisen’s paper “Uber Umlagerung von Phenol-allyl-athern in C-allyl-phenole^ describing his now eponymous rearrangement’ was observed. And what a gem it has proved to he! Ironically, the majority of the text of the paper and all the experimental details dealt with the substance of the title while the first paragraph mentioned, in almost parenthetical fashion, the rearrangement of the 0-allylation product of ace- toacetic ester 1 to its C-allylated isomer 2 upon distil- lation in the presence of ammonium chloride. Arguably, the aliphatic rearrangement has stimulated more in- terest in both its mechanistic and synthetic aspects than its aromatic counterpart. Today, the aliphatic Claisen rearrangement is but one member of the class of [3,3] sigmatropic rearrangements. The prototype for the rearrangement is the transformation of allyl vinyl ether 3 into 4-pentenal (4).
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