CO₂ or SO₂: Should It Stay, or Should It Go?

Abstract

A broad computational analysis of carboncentered radical formation via the loss of either CO 2 or SO 2 from the respective RXO 2 radical precursors (X = C or S) reveals dramatic differences between these two types of dissociative processes. Whereas the C−C scission with the loss of CO 2 is usually exothermic, the C−S scission with the loss of SO 2 is generally endothermic. However, two factors can make the C−S scissions thermodynamically favorable: increased entropy, characteristic for the dissociative processes, and stereoelectronic influences of substituents. The threshold between endergonic and exergonic C−S fragmentations depends on subtle structural effects. In particular, the degree of fluorination in a radical precursor has a notable impact on the reaction outcome. This study aims to demystify the intricacies in reactivity regarding the generation of radicals from sulfinates and carboxylates, as related to their role in radical cross-coupling.

Utilization of C(sp3)‐Carboxylic Acids and Their Redox‐Active Esters in Decarboxylative Carbon−Carbon Bond Formation

“…A reductive elimination then provides the desired product. Reactions that reflect this classification are presented in Schemes 6,8,9,10,11,12,13,31,35,37,39 and 64. Besides that, a few examples that engage in oxidative decarboxylation pathways in the presence of super-stoichiometric external oxidant are indicated in Schemes 21, 22, 42 (omitted in Figure 1).…”

Spatial-confinement induced electroreduction of CO and CO2 to diols on densely-arrayed Cu nanopyramids

“…With the cleavage of αC–OH bond as a consequence, αC forms a stronger bond with surface Cu with shorter bond length so as to conform to the octet rule (namely, that every carbon atom must form four covalent bonds to achieve a stable structure with eight electrons in the valence shell). 51 The *C–CHO transformation is not facile to proceed on Cu-DAN because the spatial confinement restricts both sides of the intermediate from stretching, and consequently relocates αC to hexagonal close packed (HCP) site (Fig. S20 † ).…”

Recent Advances in Radical Reactions of Vinyl Triflates and Their Derivatives

“…Isopropyl cyano radical IV, which is generated by the thermal decomposition of AIBN, adds to the vinyl triflate, followed by elimination of 43 21 and CF 3 SO 2 radical III. Next, the CF 3 SO 2 radical III undergoes -cleavage to generate trifluoromethyl radical I, 22 which adds to vinyl triflate 41 to furnish benzyl radical VI. Subsequently, VI affords -trifluoromethylated product 42 and CF 3 SO 2 radical III via -cleavage, which maintains the radical chain.…”