An Asymmetric Hydrogenation/N‐Alkylation Sequence for a Step‐Economical Route to Indolizidines and Quinolizidines

Abstract

The direct catalytic asymmetric hydrogenation of pyridines for the synthesis of piperidines remains a challenge. Herein, we report a one‐pot asymmetric hydrogenation of pyridines with subsequent N‐alkylation using a traceless Brønsted acid activation strategy. Catalyzed by an iridium‐BINAP complex, the substrates undergo ketone reduction, cyclization and pyridine hydrogenation in sequence to form indolizidines and quinolizidines. The absolute configuration of the stereocenter of the alcohol is retained and influences the formation of the second stereocenter. Experimental and theoretical mechanistic studies reveal that the chloride anion and certain noncovalent interactions govern the stereoselectivity of the cascade reaction throughout the catalytic process.

Interface‐Targeting Carrier‐Catalytic Integrated Design Contributing to Lithium Dihalide‐Rich SEI toward High Interface Stability for Long‐Life Solid‐State Lithium‐Metal Batteries

“…Strong peaks at 3342 cm −1 and 1670 cm −1 could be obviously observed in the monomer TAPB, Br‐TPC and TPC, corresponding to the stretch of N−H bond and C=O bond, respectively. Both the characteristic peak of N−H and C=O almost disappeared in the FTIR spectra of Br‐TPOM and TPOM, demonstrating the successful conversion of the amine and aldehyde groups [25,26] . The solid‐state 13 C cross polarization magic‐angle‐spinning (CP/MAS) NMR spectra in Figure S2 further demonstrating the integrity of the chemical structure about Br‐TPOM.…”

Bio‐Inspired Polyanionic Electrolytes for Highly Stable Zinc‐Ion Batteries

“…Bio-inspired anionic coating could effectively modify the defect of the Zn anode, suppressing the tip effect. As stated by Liu et al, [30,31] the presence of polar groups exhibiting varying steric hindrances plays a pivotal role in governing the formation of the SEI. Therefore, for the anionic coating, attraction of À COO À to Zn 2 + form an in situ SEI layer, allowing the formation of the acceleration channel for plating.…”

Interface‐Targeting Carrier‐Catalytic Integrated Design Contributing to Lithium Dihalide‐Rich SEI toward High Interface Stability for Long‐Life Solid‐State Lithium‐Metal Batteries

“…Both the characteristic peak of NÀ H and C=O almost disappeared in the FTIR spectra of Br-TPOM and TPOM, demonstrating the successful conversion of the amine and aldehyde groups. [25,26] The solid-state 13 C cross polarization magic-angle-spinning (CP/MAS) NMR spectra in Figure S2 further demonstrating the integrity of the chemical structure about Br-TPOM. The resonance peak at ~25 ppm corresponds to tertiary carbon on the bridge, whereas a broad peak ranging between 100 and 150 ppm is attributed to the aromatic carbon atoms in the polymeric framework.…”