Walk Rearrangements in [n.1.0] Bicyclic Compounds

The Study of Reactive Intermediates in Condensed Phases

“…The physical organic chemistry literature carries numerous reports of reactive intermediates apparently not adhering to the code of conduct elucidated in the previous section . Such reports were especially prevalent in the years following the publication of the Woodward–Hoffmann rules for pericyclic reactions, as experimentalists set about the task of assessing whether nominally pericyclic processes were actually single-step, concerted reactions, or whether they occurred in a stepwise fashion, involving intermediates. − Attempts to test for intermediates by the symmetry criterion alluded to in section frequently led to ambiguous results. For many reactions, there was evidence of branching to more than one productan outcome seemingly inconsistent with a single-step mechanismbut product ratios were often not consistent with the anticipated symmetries of the putative intermediates.…”

Understanding the decomposition reaction mechanism of chrysanthemic acid: a computational study

“…Sasaki et al [10] and Ueda and Matsui [11] found that carbons 1 and 2 (Scheme 1) of the main cyclopropane group are cleaved, subsequently leading to the formation of a diradical according to Elliot and Janes [12]. The photochemistry of simple cyclopropanes has been examined by several workers [13-18] and the fundamental photochemical transformations are generally observed. For instance, the photodegradation of pyrethrins in sunlight is rapid and results in the isomerization of the side-chains, photooxidation to a variety of carboxylic acids, and isomerization of the cyclopropane acids.…”