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Article

New Bifunctional Bis(azairidacycle) with Axial Chirality via Double Cyclometalation of 2,2′-Bis(aminomethyl)-1,1′-binaphthyl

1
Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 2-12-1-E4-1 O-okayama, Meguro-ku, Tokyo 152-8552, Japan
2
Hazardous Materials Laboratory, Research and Development Division, National Research Institute of Fire and Disaster, Jindaiji-higashimachi 4-35-3, Chofu, Tokyo 182-8508, Japan
*
Author to whom correspondence should be addressed.
Deceased on 21 April 2017.
Academic Editor: Vincent Ritleng
Molecules 2021, 26(4), 1165; https://doi.org/10.3390/molecules26041165
Received: 31 January 2021 / Revised: 16 February 2021 / Accepted: 18 February 2021 / Published: 22 February 2021
As a candidate for bifunctional asymmetric catalysts containing a half-sandwich C–N chelating Ir(III) framework (azairidacycle), a dinuclear Ir complex with an axially chiral linkage is newly designed. An expedient synthesis of chiral 2,2′-bis(aminomethyl)-1,1′-binaphthyl (1) from 1,1-bi-2-naphthol (BINOL) was accomplished by a three-step process involving nickel-catalyzed cyanation and subsequent reduction with Raney-Ni and KBH4. The reaction of (S)-1 with an equimolar amount of [IrCl2Cp*]2 (Cp* = η5–C5(CH3)5) in the presence of sodium acetate in acetonitrile at 80 °C gave a diastereomeric mixture of new dinuclear dichloridodiiridium complexes (5) through the double C–H bond cleavage, as confirmed by 1H NMR spectroscopy. A loss of the central chirality on the Ir centers of 5 was demonstrated by treatment with KOC(CH3)3 to generate the corresponding 16e amidoiridium complex 6. The following hydrogen transfer from 2-propanol to 6 provided diastereomers of hydrido(amine)iridium retaining the bis(azairidacycle) architecture. The dinuclear chlorido(amine)iridium 5 can serve as a catalyst precursor for the asymmetric transfer hydrogenation of acetophenone with a substrate to a catalyst ratio of 200 in the presence of KOC(CH3)3 in 2-propanol, leading to (S)-1-phenylethanol with up to an enantiomeric excess (ee) of 67%. View Full-Text
Keywords: bifunctional catalyst; metal-ligand cooperation; dinuclear complex; iridacycle; cyclometalation; asymmetric transfer hydrogenation; cyanation; 1,1-binaphthyl; axial chirality bifunctional catalyst; metal-ligand cooperation; dinuclear complex; iridacycle; cyclometalation; asymmetric transfer hydrogenation; cyanation; 1,1-binaphthyl; axial chirality
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MDPI and ACS Style

Sato, Y.; Kawata, Y.; Yasui, S.; Kayaki, Y.; Ikariya, T. New Bifunctional Bis(azairidacycle) with Axial Chirality via Double Cyclometalation of 2,2′-Bis(aminomethyl)-1,1′-binaphthyl. Molecules 2021, 26, 1165. https://doi.org/10.3390/molecules26041165

AMA Style

Sato Y, Kawata Y, Yasui S, Kayaki Y, Ikariya T. New Bifunctional Bis(azairidacycle) with Axial Chirality via Double Cyclometalation of 2,2′-Bis(aminomethyl)-1,1′-binaphthyl. Molecules. 2021; 26(4):1165. https://doi.org/10.3390/molecules26041165

Chicago/Turabian Style

Sato, Yasuhiro, Yuichi Kawata, Shungo Yasui, Yoshihito Kayaki, and Takao Ikariya. 2021. "New Bifunctional Bis(azairidacycle) with Axial Chirality via Double Cyclometalation of 2,2′-Bis(aminomethyl)-1,1′-binaphthyl" Molecules 26, no. 4: 1165. https://doi.org/10.3390/molecules26041165

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