Developing mild and sustainable strategies for the synthesis of complex molecules is a pivotal yet challenging goal in modern synthesis. While cobalt catalysis offers a sustainable alternative to noble metals, achieving such transformations at room temperature remains elusive. Herein, we report a cobalt-catalyzed aerobic oxidative asymmetric formal cycloaddition involving C(sp²)–H bond activation of benzamides with unactivated alkynes at room temperature using air as the oxidant. For challenging low-activity substrates, reaction efficiency is enhanced via a photoinduced catalytic cycle. Mechanistic and substrate scope studies indicate that substrate reactivity is influenced by electronic and steric effects.

Asymmetric hydrogenation is an efficient tool for rapid synthesis of a diverse range of chiral compounds with high yields and excellent enantioselectivities. Chiral 2-methyl-1,2,3,4-tetrahydro-quinoline is a valuable building block for organic synthesis and has been widely used in the synthesis of bioactive molecules and chiral ligands. Herein, we report an improved iridium-catalyzed asymmetric hydrogenation of 2-methylquinoline on a hundred-gram scale for efficient synthesis of chiral 2-methyl-1,2,3,4-tetrahydroquinoline with up to 91.4% ee value and an 80,000 turnover number. Optically pure 2-methyl-1,2,3,4-tetrahydroquinoline could be obtained in high yields through recrystallization or chemical resolution with the tartaric acid derivative (L)-DMTA.

Cholesteric liquid crystal polymer network (CLCN) patterns composed of oppositely handed helical structures are attractive for anti-counterfeiting. Different areas can be observed under the circularly polarized light with opposite handedness. However, achieving precise control over the reflection band wavelengths of CLCN patterns using photochromic cholesteric liquid crystals (CLCs) remains a significant challenge. Herein, we synthesized a chiral cyanostilbene derivative that demonstrated significant modulation of its helical twisting power upon 365 nm ultraviolet (UV) irradiation. When incorporated into CLC mixtures, this additive enabled precise control over both the handedness and reflection wavelength of the resulting CLCN patterns within seconds under UV exposure. The system allowed for the preparation of colorful CLCN patterns through in-situ photopolymerization. These findings demonstrate that the developed CLC mixtures are well-suited for high-throughput fabrication of CLCN patterns on industrial coating lines.

O-Silylated hemiaminals are utilized as elegant imine precursors in the formal asymmetric [4+2] annulation of indoles for the first time, wherein chiral phosphoric acid (CPA) acts (1) as a Brønsted acid catalyst to facilitate methanimine formation under mild conditions and then (2) as an anion-binding catalyst for dearomative annulation. This methodology exhibits a broad substrate scope with remarkable functional group tolerance and enantioselectivity (up to 97% yield and 99% ee), providing straightforward access to the challenging indoline-fused tetrahydroquinolines bearing multiple stereogenic centers. Mechanistic studies reveal the critical role of PhNHCO- groups in enhancing both reactivity and enantioselectivity, probably due to non-covalent interactions with CPA. The kinetic isotope effects experiment and negative linear Hammett correlation suggest a concerted process.

Transition metal-catalyzed asymmetric C–H activation is vital for chiral molecule synthesis but faces challenges in remote C–H functionalization due to traditional metallacycle constraints and difficulties in long-range chiral recognition. This review summarizes three core strategies to address these issues: template-assisted chiral ligand control, norbornene-mediated palladium catalysis, and bifunctional catalyst control. These strategies achieve high enantioselectivity for diverse chiral architectures. Future directions include expanding to para-C–H bonds of arenes and aliphatic C–H bonds, developing robust chiral mediators/ligands, and applying the methodology to natural products and complex materials.