Novel aspects of carbonyl oxide chemistry

Abstract

The structural and chemical properties of 1,3-dipolar peroxidic species (X-O-O) such as ozone (X = O) and carbonyl oxides (X = R 2 C) depend significantly on the nature of X. Although cyclic O 3 is thermodynamically unstable, dioxiranes, cyclic isomers of carbonyl oxides, are isolable and have been fully characterized. In contrast to the well known electrophilic nature of ozone, carbonyl oxides usually act as a nucleophilic oxygen transfer agent, but their reactivity could be altered by substituents. It is expected that the chemistry of R 2 C-O 2 species will provide a good starting point for a better understanding of dioxygen complexes (X-O 2 ) with various Xs. Interesting aspects of carbonyl oxide chemistry are discussed, including methods of generation, cyclization to dioxiranes and the nature of their oxygen transfer activities.

Crystal structures and photoreactivity of trans- and cis-valerophenone diperoxides

“…The observation (ii) is as expected, since the reaction is generally more selective in crystals than in a solution. Scheme 3 describes another possible decomposition pathway (path b), where the cleavage of two C-O bonds occurs first and the ensuing carbonyl oxide intermediate, as recently described in a review [35], leads mainly to the formation of ester 3. It may be assumed that path b is occurring to some extent in the solution, since the 2/3 selectivity is low.…”

Thioformaldehyde S-Sulfide, Sulfur Analogue of the Criegee Intermediate: Structures, Energetics, and Rovibrational Analysis

“…For reference, the lighter congener of dithiirane, dioxirane ( 1c ), can undergo homolytic O–O cleavage to yield dioxymethylene, which subsequently decomposes to furnish simpler downstream molecules such as CO 2 . Conversely, the Criegee intermediate ( 1b ) combines with formaldehyde ( 1d ) to generate the canonical product, 1,2,4-trioxolane ( 1e ) . It is likely that the sulfur analogues exhibit equally rich but unknown chemistry.…”

“…14 Conversely, the Criegee intermediate (1b) combines with formaldehyde (1d) to generate the canonical product, 1,2,4trioxolane (1e). 15 It is likely that the sulfur analogues exhibit equally rich but unknown chemistry.…”

Reactions of thermally generated benzynes with six-membered N-heteroaromatics: pathway and product diversity

“…VIII to IX ). Formation of 7 , on the other hand, can be rationalized by an intramolecular proton-transfer within the initially formed 1,3-zwitterion VIII and subsequent oxidation of the resulting carbene X by oxygen 12. This type of reactivity was earlier reported by Biju and coworkers 10 c .…”