Stereoelectronic power of oxygen in control of chemical reactivity: the anomeric effect is not alone

Abstract

The chameleonic properties of oxygen accounts for the diverse reactivity of O-functionalities and their profound role in organic synthesis.

MOF-Zn-NHC as an efficient N-heterocyclic carbene catalyst for aerobic oxidation of aldehydes to their corresponding carboxylic acids via a cooperative geminal anomeric based oxidation

“…Also, we recently wrote a comprehensive review article about the stereoelectronic power of oxygen in controlling the chemical reactivity. 50 …”

BF3 Mediated [1,5]‐Hydride Shift Triggered Cyclization: Thioethers Join the Game

“…Unlike the intricate energetic trend in transition states X‐TS1‐Ch , the trend for intermediates X–IM1 agrees well with the conventional cation stability. The intermediate S‐IM1 is stabilized by sulfur‐carbocation orbital interactions, [28,29] while C–IM1 is not, which makes it only 3.5 kcal/mol lower than the preceding transition state. However, formation of these intermediates does not influence the reaction rates, that explains the above mentioned discrepancy between the rate of the process and the stability of the forming cation.…”

Nature of the Trigger Linkage in Explosive Materials Is a Charge-Shift Bond

“…Here, as schematically depicted in Figure , it refers specifically to the donation of electron density from in-plane oxygen lone pairs of −NO 2 to the antibonding σ (X–N) * orbital. The magnitude of negative hyperconjugation depends on the extent of orbital overlap ( S ij ) between the σ (X–N) * antibonding bond orbital and the oxygen lone pairs, as well as on how low in energy is σ (X–N) * . Hence, the larger the coefficient of the σ (X–N) * orbital on the N-atom and the more electronegative is X, the greater will be the magnitude of negative hyperconjugation.…”

“…Here, the second-order stabilization energy E(2) associated with the interaction between oxygen lone pairs and the antibonding σ (X–N) * bond orbital can be considered as the magnitude of hyperconjugation (Table S3). As illustrated in Figure , the magnitudes of hyperconjugation and the RE CS value for the three representative classes of trigger linkages increase in the same order (realistic explosives are discussed in Section ).…”