Regio- and stereo-selective olefinic C–H functionalization of aryl alkenes in ethanol

Abstract

We report on N,N-bidentate-chelation-assisted α- and β-olefinic C-H alkenylation of aryl alkenes in ethanol to afford aryl dienes/trienes with excellent regio- and stereo-selectivities. The reaction of 2-alkenyl benzylamine and benzoic...

Recent Advances in Alkenyl sp2 C–H and C–F Bond Functionalizations: Scope, Mechanism, and Applications

“…Around the same time, Zhang et al investigated the N,Nbidentate-chelation-assisted α-selective vinylic C−H bond functionalization of styrene derivatives (Scheme 24). 71 The 8-aminoquinoline (AQ) was readily employed as the bidentate directing group of best choice. By the combination of Pd(OAc) 2 /benzoquinone (BQ), MnO 2 oxidant, and PivOH additive in EtOH at 60 °C, a wide substrate scope (25 examples) of vinylic α-C(sp 2 )−H olefination product was documented in satisfactory yields of up to 92%.…”

Transition metal-catalyzed double Cvinyl–H bond activation: synthesis of conjugated dienes

“…In 2022, a methodology for the regio-/stereo-selective C–H alkenylation of aryl alkenes using a N , N -bidentate as a directing group via a Pd( ii )-catalysis in ethanol was reported by Zhang and co-workers (Scheme 79). 111 Different N , N -bidentate directing groups were explored for this reaction. Following optimization of the reaction conditions, 2-vinyl benzamides 173 containing 8-aminoquinoline (AQ) and 2-pyrazinamide (PC) as directing groups were found to be the perfect choice for carrying out the α-C–H alkenylation reaction.…”

“…In continuation to the previous work 111 (Scheme 79), Zhang research group further focused on the asymmetric β-C–H alkenylation of styrenes 179 using transient chiral auxiliaries (Scheme 80). 112 Authors used transient directing groups derived from aldehyde and easily available amino acids as ligands.…”

Functionality‐Directed Regio‐ and Enantio‐Selective Olefinic C−H Functionalization of Aryl Alkenes

“…Gram-scaled preparation is successful and the directing group was easily to be removed to afford benzyl amine for further chemical derivation (Scheme 23). [26] Scheme 20. Ru-catalyzed [5 + 1] annulation of 2-alkenylanilines with sulfoxonium ylides toward quinolines (Ma and Nan, 2019).…”