Halogen-Atom Transfer Enabled Catalytic Enantioselective Coupling to Chiral Trifluoromethylated Alkynes via Dual Nickel and Photocatalysis.

With halogen-atom transfer as an effective tool, a novel catalytic enantioselective protocol to generate chiral trifluoromethylated alkynes has been established by a cooperative photoredox and nickel catalysis system, providing a straightforward and modular route to access this type of product in good yields and enantioselectivities. The halogen-atom transfer process is essential for the reaction and this novel strategy offers another promising way to utilize alkyl halides with highly negative reduction potentials. It firstly expands nickel-catalyzed asymmetric reductive cross-couplings of organohalides from the traditional single-electron transfer to halogen-atom transfer.

Selectively Tunable Synthesis of α-Trifluoromethyl Ketones.

A cross-coupling of aldehydes and α-trifluoromethyl alkyl bromides was developed via dual nickel/photoredox catalysis system. A wide variety of substrates bearing a diverse set of functional groups were compatible to afford α-trifluoromethyl ketones under very mild conditions (visible light, ambient temperature, no strong base). Selectively tunable access to these ketones with the trifluoromethyl group on any one side can be smoothly obtained by simply modulating different reagents. Meanwhile, the asymmetric pattern was also investigated.

Cascade reaction of o-enoyl arylisocyanide and o-hydroxy aromatic aldimine: diastereoselective access to a polycyclic spirobenzoxazine chromeno[4,3-b]pyrrole derivative.

A series of structurally unusual spirobenzoxazine chromeno[4,3-b]pyrrole derivatives have been efficiently constructed in a single operation from readily available starting materials. This domino transformation forms successively three new rings and provides a fast and economic strategy with excellent diastereoselectivity.

Diastereoselective Synthesis of Tetracyclic Tetrahydroquinoline Derivative Enabled by Multicomponent Reaction of Isocyanide, Allenoate, and 2-Aminochalcone.

We report here a multicomponent protocol to assemble several polycyclic dihydropyran-fused tetrahydroquinoline structures with excellent diastereoselectivity. This procedure employs simple feedstocks to accomplish a series of diverse structures, which is difficult to attain by traditional sequences.