Molecular Rearrangements

This Chapter Contains Sections titled: Pericyclic Reactions Reviews Cycloaddition–Cycloreversion Ene Reaction Sigmatropic Shifts Electrocyclic Reactions Molecular Rearrangements Acid Catalysed Base Catalysed Small Ring Rearrangements 1,2-Rearrangement Alkyl Shifts Ring Expansion Ring Opening and Ring Closure Oxidation Reduction Phosphorus Photochemical Reactions Radical and Biradical Thermal Named Reactions Achmatowicz Reaction Balysis–Hillman Beckmann Bergmnan Brook Cloke–Wilson Rearrangement Curtius Dimroth Rearrangement Fischer Indole Friedel–Crafts Heyns Rearrangement Lossen Rearrangement Meyer–Schuster Mislow–Evans Morita–Baylis–Hillman Nazarov Phospho-Fries Ritter Reaction Smiles Stevens Trost–Rychnovsky Reaction Wittig Wolff Rearrangement Metal Catalysed Aluminium Cobalt Copper Gold Iridium Iron Nickel Ruthenium Rhodium Silver Palladium Platinum Vanadium Miscellaneous References This chapter provides a review on the applicability of the frontier orbital theory to transition-metal and lanthanide-mediated intramolecular and metathesis reactions. It reviews of Bronsted acid catalysts for asymmetric induction in pericyclic reactions which has reported promising examples that rely on multiple non-covalent interactions in the transition state. The chapter gives the pericyclic reactions of enediynes, enyne-cumulenes, and yne-diynes. It reports the Claisen rearrangements of 3-oxa-1,5-hexadienes in which one or more carbon atoms were replaced with atoms different than carbon. The regioselectivity of the 2+2-photocycloaddition of 2-pyridone and methylacrylate has been studied using ab initio molecular orbital methods and the results explained from the conformation of parallel-type conical intersections. Computational studies show that the Diels–Alder pathway is favoured in the enzyme environment.