Regioselective aliphatic C–H functionalization using frustrated radical pairs

Insights into Single-Electron-Transfer Processes in Frustrated Lewis Pair Chemistry and Related Donor–Acceptor Systems in Main Group Chemistry

“…During correction of the proofs, the article of Lin et al was published that highlighted the potential of in-situ generated radical pairs for the regioselective aliphatic C−H functionalization. 85 More understanding of the fundamental radical steps should help to stir the development of radical mechanisms, ultimately also leading to more selective pathways or higher reaction rates as typical single-electron-transfer steps and radical mechanisms have low energy barriers. It is especially noteworthy that employing irradiation can potentially lead to increased reaction rates through photoinduced SET events.…”

“…We hope this review leads to more insights and understanding of the SET process in FLP chemistry and related donor–acceptor systems in main group chemistry, which can aid the design of new chemical conversions previously unknown in the two-electron paradigm. During correction of the proofs, the article of Lin et al was published that highlighted the potential of in-situ generated radical pairs for the regioselective aliphatic C−H functionalization . More understanding of the fundamental radical steps should help to stir the development of radical mechanisms, ultimately also leading to more selective pathways or higher reaction rates as typical single-electron-transfer steps and radical mechanisms have low energy barriers.…”

Frustrated Radical Pairs in Organic Synthesis

“…Achieving an efficient and selective C(sp 47 Upon formation, HMDS • is highly electrophilic and an excellent hydrogen-atom acceptor (HAA) (BDE N−H = 109 kcal/mol), whereas TEMPO • shows high affinity to transient radicals and can capture C-centered radicals at rates often near the diffusion limit. Indeed, we showed that this radical pair is strongly reactive yet frustrated due to their sizes and weak bonding interactions and is able to split aliphatic C−H bonds via a homolytic pathway, giving rise to C−H aminoxylated product 14-2 along with hexamethyldisilazane (Scheme 14B).…”

“…The main challenge in this goal, however, arises from the strong and ubiquitous nature of the C–H bonds in organic molecules. Recently, we developed a new class of FRPs composed of persistent TEMPO • and transient hexamethyldisilazide radical (HMDS • ), which are formed readily from lithium hexamethyldisilazide (LiHMDS) and TEMPO + precursors (Scheme A) . Upon formation, HMDS • is highly electrophilic and an excellent hydrogen-atom acceptor (HAA) (BDE N–H = 109 kcal/mol), whereas TEMPO • shows high affinity to transient radicals and can capture C -centered radicals at rates often near the diffusion limit.…”

Electron delocalization in defect-containing graphene and its influence on tetrel bond formation

“…3,4,10,11 Moreover, it is known that the simultaneous coexistence of sterically hindered Lewis acids and Lewis bases within one material promotes its catalytic activity towards H 2 activation. 12,13 According to the general understanding of frustrated Lewis pairs in graphene, [14][15][16] to obtain a frustrated Lewis pair in graphene usually requires doping with N or P atoms to form the centres of the Lewis bases and with various carriers of B, Al, or Ga atoms as the Lewis acids. The emergence of these active sites due to point defects in graphene demonstrates its high chemical potential for use in catalytic processes.…”