Palladium‐Catalyzed Enantioselective Narasaka–Heck Reaction/Direct C−H Alkylation of Arenes: Iminoarylation of Alkenes

Abstract

A palladium‐catalyzed reaction of γ,δ‐unsaturated oxime esters with oxadiazoles afforded dihydropyrroles in good to excellent yields through an intramolecular iminopalladation/intermolecular direct heteroarene C−H alkylation cascade. This unprecedented iminoarylation of alkenes was subsequently realized in an enantioselective manner in the presence of a chiral bidentate phosphine ligand (Synphos).

Nickel-Catalyzed Enantioselective Desymmetrizing Aza-Heck Cyclization of Oxime Esters

“…17,18 Tsutsui and Narasaka 19 pioneered the prototypical aza-Heck cyclization process of pentafluorobenzoyl ( F Bz) oxime esters, and more recently, a variety of other nitrogen electrophiles have been identified (Scheme 1a). [20][21][22][23][24][25][26][27][28][29][30] Nickel (Ni) has numerous advantages as a catalyst, including natural abundance, affordability, and chemical sustainability. 31 Recent years also witnessed a surge of interest in Ni-catalyzed asymmetric tranformations, [32][33][34][35][36][37][38] but Ni-catalyzed enantioselective Heck reactions still remain underdeveloped among them.…”

Iron‐Catalysed Remote C(sp3)−H Azidation of O‐Acyl Oximes and N‐Acyloxy Imidates Enabled by 1,5‐Hydrogen Atom Transfer of Iminyl and Imidate Radicals: Synthesis of γ‐Azido Ketones and β‐Azido Alcohols

“…In addition to the classic Beckmann [1] and Neber rearrangements, [2] the O-acyl oximes can also be converted into the organometallic species via oxidative addition, [3] into the iminyl radicals by single-electron transfer (SET) reduction, [4] and into the iminatometal speciest hrough two consecutive SET processes. [5][6] Amongt hese transformations, the 5-exo-trig cyclisationsofg,dunsaturated oxime esters via either iminopalladium [3,7] or iminyl radicali ntermediates [4,[8][9][10] have been developed into powerful synthetic tools that have been extensively exploited for the synthesis of pyrrolidines and related N-heterocycles of biological importance.…”

Copper‐Catalyzed Enantioselective Arylative Desymmetrization of Prochiral Cyclopentenes with Diaryliodonium Salts

“…In connection with our ongoing research interest in the transition-metal-catalyzed enantioselective carbofunctionalization of alkenes, [19] we became interested in the enantioselective copper-catalyzed arylation of alkenes and documented recently an enantioselective arylative semipinacol rearrangement. [18b] We report herein the first examples of the coppercatalyzed enantioselective arylative desymmetrization of prochiral 4-substituted and 4,4-disubstituted cyclopentenes with diaryliodonium salts for the synthesis of enantiomerically enriched cyclopentenyl carboxamides,c yclopentenyl alcohols,a nd N-cyclopentenyl pivalamides with high to excellent ee values (Scheme 1c).…”