Highly Enantioselective Insertion of Carbenoids into NH Bonds Catalyzed by Copper(I) Complexes of Binol Derivatives

Abstract

Sekundäre Amine können es auch! Die erfolgreiche katalytische asymmetrische Insertion von α‐Diazoestern in die N‐H‐Bindung unterschiedlich substituierter Amine wird vorgestellt (siehe Schema; M.S.=Molekularsieb). Mit einer Vielzahl an Substraten wurden ausgezeichnete Enantioselektivitäten (bis 98 % ee) und hohe Ausbeuten (bis 99 %) unter milden Reaktionsbedingungen erhalten.

Asymmetric NH Insertion Reaction Cooperatively Catalyzed by Rhodium and Chiral Spiro Phosphoric Acids

“…[3] In initial studies, chiral dirhodium catalysts were tested in intramolecular [4] and intermolecular [5] NÀH insertion reactions, however, only low to modest enantioselectivities (< 50 % ee) were achieved. Since these reports, other transition metals including copper and silver have been used as catalysts, and gave enantioselectivities up to 48 % ee.[6]Recently, we reported a highly enantioselective NÀH insertion reaction (up to 98 % ee) using a copper complex with chiral spiro bisoxazoline ligands.[7] Subsequently, two other types of chiral copper catalysts have been developed, one with a planar chiral bipyridine ligand [8] and the other with a binolderivative ligand, [9] and both of these catalysts give high enantioselectivities in NÀH insertion reactions.Although progress on copper-catalyzed asymmetric NÀH insertion reactions has been substantial, they still have serious limitations. For instance, all the copper-catalyzed N À H insertion reactions require high catalyst loading (5-10 mol %) for satisfactory yields and enantioselectivities, thus more-efficient chiral catalysts are highly desirable.…”

“…The chiral induction occurs in the protontransfer step. The dirhodium catalyst is most likely involved in the proton-transfer step, considering its strong influence on the enantioselectivity of the reaction (see Table 1, entries [9][10][11][12][13][14]. According to this mechanism, the chiral SPA acts as a proton-transfer shuttle.…”

Copper‐Catalyzed NH Insertion and Oxidative Aromatization Cascade: Facile Synthesis of 2‐Arylaminophenols

“…Even though Yates reported the first copper‐catalyzed NH insertion (NHI) of diazo acetates over 60 years,3 the introduction of dirhodium(II) catalysts made this reaction practical in organic synthesis 4. Recently, the groups of Zhou,5 Fu,6 and Feng7 reported the copper‐catalyzed enantioselective NHI, in which privileged ligands were required to achieve high enantioselectivity as well as good reactivity. Recent reports highlighted the combination of copper‐catalyzed NHI with other transformations in one‐pot,8 which further broadened the application of copper carbenoid chemistry.…”

Asymmetric NH Insertion Reaction Cooperatively Catalyzed by Rhodium and Chiral Spiro Phosphoric Acids

“…[6] Recently, we reported a highly enantioselective NÀH insertion reaction (up to 98 % ee) using a copper complex with chiral spiro bisoxazoline ligands. [7] Subsequently, two other types of chiral copper catalysts have been developed, one with a planar chiral bipyridine ligand [8] and the other with a binolderivative ligand, [9] and both of these catalysts give high enantioselectivities in NÀH insertion reactions.Although progress on copper-catalyzed asymmetric NÀH insertion reactions has been substantial, they still have serious limitations. For instance, all the copper-catalyzed N À H insertion reactions require high catalyst loading (5-10 mol %) for satisfactory yields and enantioselectivities, thus more-efficient chiral catalysts are highly desirable.…”

“…[6] Recently, we reported a highly enantioselective NÀH insertion reaction (up to 98 % ee) using a copper complex with chiral spiro bisoxazoline ligands. [7] Subsequently, two other types of chiral copper catalysts have been developed, one with a planar chiral bipyridine ligand [8] and the other with a binolderivative ligand, [9] and both of these catalysts give high enantioselectivities in NÀH insertion reactions.…”