NbCl5-catalyzed sulfa-Michael addition for constructing quaternary centers in enones.

A novel NbCl5-catalyzed sulfa-conjugate addition has been developed to construct quaternary centers in various enones. This new method enables a range of functionalized thiols to access different ß-sulfido carbonyl compounds bearing a quaternary center. 27 novel ß-sulfido ketones have been obtained with moderate to excellent yields. The preparative scale reactions also proceed well, showing no decrease in yield. We further studied the mechanism by DFT calculations. This methodology is significant in sulfur chemistry, especially in sulfa-conjugate addition, giving a new pathway to add thiols to tri-substituted enones.

Visible-Light Organophotoredox-Mediated [3 + 2] Cycloaddition of Arylcyclopropylamine with Structurally Diverse Olefins for the Construction of Cyclopentylamines and Spiro[4.n] Skeletons.

We developed a visible-light-mediated [3 + 2] cycloaddition of arylcyclopropylamine with structurally diverse olefins using QXPT-NPh as a highly efficient organic photoredox catalyst. We first achieved the use of various alkyl-substituted alkenes in intermolecular [3 + 2] cycloadditions with cyclopropylamine. We also developed a general and efficient strategy for the construction of structurally diverse cyclopentane-based spiro[4.n] skeletons with 1,3-difunctional groups, which broadly exist in natural products and synthetic molecules. Furthermore, we proposed a hydrogen-bond mode between the arylcyclopropylamine and the photocatalyst QXPT-NPh.

Formal Syntheses of (-)-Quinocarcinamide and (-)-Quinocarcin.

Concise and scalable formal syntheses of (-)-quinocarcinamide and (-)-quinocarcin have been achieved in 9 steps with 9% overall yield from simple commercially available chemicals. The synthetic strategy features an ortho-regioselective Pictet-Spengler cyclization for the construction of the tetrahydroisoquinoline skeleton, a stereoselective formal intramolecular [3 + 2] cross cycloaddition of cyclopropane 1,1-diester with an imine for the construction of the 3,8-diazabicyclo[3.2.1]octane skeleton.

Poly lactic-co-glycolic acid-based nanoparticles as delivery systems for enhanced cancer immunotherapy.

Cancer has emerged as one of the most severe diseases in modern times, various therapies have advanced remarkably in recent decades. Unlike the direct therapeutic targeting tumor cells, immunotherapy is a promising strategy that stimulate the immune system. In cancer immunotherapy, polymeric-based nanoparticles can serve as deliver systems for antigens and immunostimulatory molecules, and they have attracted increasing attention and revolutionized cancer therapy. Poly (lactic-co-glycolic acid) (PLGA) is the most frequently used clinically approved biodegradable polymer and has a broad scope of modification of its inherent properties. Recent advances in PLGA based drug delivery systems in cancer immunotherapy have been described in this mini review, with special emphasis on cancer vaccines and tumor microenvironment modulation.

Highly efficient construction of an oxa-[3.2.1]octane-embedded 5-7-6 tricyclic carbon skeleton and ring-opening of the bridged ring via C-O bond cleavage.

We report herein a highly efficient strategy for construction of a bridged oxa-[3.2.1]octane-embedded 5-7-6 tricyclic carbon skeleton through [3 + 2] IMCC (intramolecular [3 + 2] cross-cycloaddition), and the substituents and/or stereochemistries on C-4, C-6, C-7 and C-10 fully match those in the rhamnofolane, tigliane and daphnane diterpenoids. Furthermore, ring-opening of the bridged oxa-[3.2.1]octane via C-O bond cleavage was also successfully achieved.