Cobalt-Catalyzed, Aminoquinoline-Directed Functionalization of Phosphinic Amide sp² C–H Bonds

Abstract

In this paper, we introduce arylphosphinic acid aminoquinoline amides as competent substrates for cobalt-catalyzed sp2 C–H bond functionalization. Specifically, the feasibility of their coupling with alkynes, alkenes, and allyl pivalate has been demonstrated. Reactions are catalyzed by simple Co(NO3)2 hydrate in ethanol or mixed dioxane/tBuOH solvent in the presence of Mn(OAc)3·2H2O additive, sodium pivalate, or acetate base and use oxygen from the air as an oxidant. Directing group removal affords ortho-functionalized P,P-diarylphosphinic acids.

Diastereoselective [3+2] Annulation of Aromatic/Vinylic Amides with Bicyclic Alkenes through Cobalt‐Catalyzed C−H Activation and Intramolecular Nucleophilic Addition

“…[16] Furthermore,intermediate II features no suitable b-hydrogen atoms for elimination to give an olefination product, [7] and the combined steric hindrance of the AQ moiety and bicyclic alkene 2a prevents the direct reductive elimination to as ixmembered lactam. [6] In summary,wehave developed acobalt-catalyzed [3+ +2] cycloaddition of aromatic/vinylic secondary amides with bicyclica lkenes.T he reaction proceeds by coordinationassisted C À Hactivation, alkene insertion, and intramolecular nucleophilic addition. Thet ransformation works well under mild reaction conditions and features abroad substrate scope.…”

“…Recently,t he groups of Daugulis, [6] Ackermann, [7] and others [8] have shown that air-stable commercially available Co II /Co III salts can be used to functionalize aromatic/vinylic C(sp 2 )ÀHbonds with alkynes/alkenes.Cobalt-catalyzed CÀH activation reactions of amides with alkenes afforded the [4+ +2] or [4+ +1] annulation products (Scheme 1). Considering the hypothesis that these reactions proceed through directing group (DG) assisted C À Ha ctivation, alkene insertion, and Scheme 1.…”

Rhodium‐Catalyzed C(sp2)‐ or C(sp3)−H Bond Functionalization Assisted by Removable Directing Groups

“…[171] 6.2.5. [173][174][175][176][177][178][179][180][181][182][183][184][185][186] Theu tility of an 8aminoquinoline moiety for the Rh-catalyzed functionalization of amides discussed here was mainly reported by Chatani and co-workers in terms of various alkylation and alkenylation reactions. [172] Thee ase of installation and removal of the 8- aminoquinoline moiety enhances the utility of its usage in synthetic chemistry and many groups have focused their studies on this directing group.…”

Cobalt‐Catalyzed Annulation Reactions via C−H Bond Activation

“…In 2016, Daugulis reported that 8‐aminoquinoline contains phosphinic amides 106 could also act as a directing group in C−H bond activation reactions (Scheme ) . Gratifyingly, Q‐phosphinic amides efficiently coupled with internal, terminal alkynes as well as alkenes affording phosphaquinolones 107 in good to excellent yields.…”