Favorskii rearrangement in bridged polycyclic compounds

Abstract

The Favorskii rearrangement has been the subject of intensive research by many organic chemists since its discovery in 1894 (1). But despite its age, the reaction remains novel. Its mechanism and stereochemistry are currently being studied. It is becoming an increasingly reliable instrument of organic synthesis. A number of earlier summaries on the Favorskii rearrangement are available (2-6). The purpose of this article is to review the more current literature on the application of this rearrangement to bridged polycyclic compounds where it has been used in the synthesis and study of strained moleketone (XV) and derivatives with substituents at C-2 such as (XVI) and (XVII) undergo ring contraction (30-33). Mc-

The Chemistry of α-Haloketones and Their Utility in Heterocyclic Synthesis

“…There are short chapters dealing with the synthesis and reactivity of halogenated ketones in Patai’s series [ 2 ] and in Houben-Weyl's series "Methoden der Organischen Chemie" [ 3 , 4 ]. In addition, the Favorskii rearrangement of α-haloketones has been reviewed by several articles [ 5 , 6 , 7 , 8 , 9 ], and the reactivity of α-haloketones towards nucleophiles was described by Tchoubar in 1955 [ 10 ]. It is our hope that by asembling a comprehensive survey of the widely scattered information on the chemistry of α-haloketones as versatile synthons in heterocyclic synthesis, this will focus new attention on the broad potential of these compounds in the synthesis and mechanistic studies of heterocyclic compounds.…”

The Lowest Singlet and Triplet States of the Oxyallyl Diradical

“…Oxyallyls are reactive intermediates, whose participation has been postulated in the ring opening of cyclopropanones [1] and allene oxides, [2] in the Favorskii rearrangement, [3] and in a variety of synthetically useful transformations. [4] The parent oxyallyl (OXA) can be viewed as a derivative of trimethylenemethane (TMM), in which one methylene group is replaced by an oxygen atom (Scheme 1).…”

Quantum chemical characterization of cycloaddition reactions between 1,3-butadiene and oxyallyl cations of varying electrophilicity

“…1) has been the subject of considerable discussion, in part owing to proposals that oxyallyls are reactive intermediates in cyclopropanone/allene oxide tautomerizations, 18,19 Favorskii rearrangements 20,21 and [4 3] cycloaddition reactions. 22,23 Oxyallyls are typically considerably less stable than their cyclopropanone (or allene oxide) valence tautomers.…”