Chiral polycyclic benzosultams from photocatalytic diastereo- and enantioselective benzylic C–H functionalization

Abstract

Asymmetric C(sp3)-H functionalization has emerged as a useful tool for simultaneous installation of functionality and chirality onto hydrocarbon units. Stereodiscrimination in reactions between a strong C(sp3)-H bond and a prochiral...

Asymmetric Paired Electrocatalysis: Enantioselective Olefin–Sulfonylimine Coupling

“…On the basis of the above-mentioned results and previous studies, , a plausible mechanism is proposed in Figure . Initially, the catalyst precursor Co II preferentially undergoes single-electron oxidation at the anode to form the Co III species, which interacts with phenylsilane to furnish the Co III –H complex.…”

Recent Advances in Carbonyl‐Photoredox/Transition Metal Dual Catalysis

“…A SET between the excited state of ClÀ TXO (ClÀ TXO*) and α-oxo acid could occur to produce a carboxyl radical (RCOCO 2 * ) and ketyl radical anion [ClÀ TXO] *À . The former could release CO 2 to afford acyl radical (RCO * , 17), which is then trapped by L n Ni II (Ar)X (19), generated by the oxidative addition of ArX to L n Ni 0 (solvent) (18), generating Ni(III) intermediate L n Ni III -(Ar)(RCO)X (20). Subsequently, 20 undergoes reductive elimination to yield the desired ketone and L n Ni I X (21).…”

“…In 2022, Gong and co-workers reported a methodology for a photocatalytic diastereo-and enantioselective CÀ H intramolecular cyclization reaction (Scheme 18). [20] Optimization of the reaction conditions involving irradiation by 455 nm LEDs, 5,7,12,14-pentacenetetrone (PT) (5 mol %), L2 (11 mol %), NiBr 2 (10 mol %), Na 2 CO 3 (1.5 equiv) in CHCl 3 effectively promoted this stereoselective C(sp 3 )À H functionalization/cyclization cascade.…”

“…In 2022, Gong and co‐workers reported a methodology for a photocatalytic diastereo‐ and enantioselective C−H intramolecular cyclization reaction (Scheme 18). [20] Optimization of the reaction conditions involving irradiation by 455 nm LEDs, 5,7,12,14‐pentacenetetrone ( PT ) (5 mol %), L2 (11 mol %), NiBr 2 (10 mol %), Na 2 CO 3 (1.5 equiv) in CHCl 3 effectively promoted this stereoselective C(sp 3 )−H functionalization/cyclization cascade. (3‐Chloropropyl)benzenes bearing electron‐withdrawing or electron‐donating groups at the para ‐position of the phenyl ring were converted into the desired chiral polycyclic benzosultams (42–82% yields, up to >20 : 1 dr, 52–98% ee).…”

Synthesis of Polycyclic Imidazolidinones via Cascade [3 + 2]-Annulation of β-Oxo-acrylamides with Cyclic N-Sulfonyl Imines

“…Comparatively, β-electron-withdrawing group (ester or carbonyl)-tethered acrylamide usually acts as a N , C α -1,3-synthon in chiral amine-catalyzed asymmetric cascade aza-Michael/Michael reaction with α, β-unsaturated aldehydes, as well as Lewis base-catalyzed formal [3 + 2]-annulation reactions with nitro-heteroarenes or isocyanates . On the other hand, cyclic N -sulfonyl imines exhibit versatile reaction activity in organocatalytic, metal-catalyzed, or radical-mediated cycloaddition reactions, which provide straightforward, powerful, and atom-economical methods to a wide range of diverse pharmacologically sultam or sulfamidate-fused nitrogen-containing heterocycles . Based on our achievements in the field of heterocyclic chemistry involving N -alkoxy α-halohydroxamate or acrylamide, and in line with our continuous efforts in annulation reactions, we have successfully established an Et 3 N-catalyzed aza-Mannich reaction triggered cascade annulation reaction of β-oxo-acrylamides with cyclic N -sulfonyl imines, leading to the formation of highly functionalized sulfamide-fused imidazolidinone derivatives (Scheme f).…”