We report a redox-neutral P(O)−N coupling reaction of P(O)−H compounds with azides via photoredox and copper catalysis, providing new access to useful phosphinamides, phosphonamides, and phosphoramides. This transformation tolerates a wide range of nucleophilic functionalities including alcohol and amine nucleophiles, which makes up for the deficiency of classical nitrogen nucleophilic substitution reactions. As a demonstration of the broad potential applications of this new methodology, late-stage functionalization of a diverse array of azidobearing natural products and drug molecules, a preliminary asymmetric reaction, and a continuous visible-light photoflow process have been developed.

Transition-metal-catalyzed sp 2 C À Nbond formation is ar eliable method for the synthesis of aryl amines.C atalytic sp 3 CÀNformation reactions have been reported occasionally, and methods that can realizeboth sp 2 and sp 3 CÀNformation are relatively unexplored. Herein, we address this challenge with amethod of catalytic decarboxylative C À Nformation that proceeds through ac ascade carboxylic acid activation, acyl azide formation, Curtius rearrangement and nucleophilic addition reaction. The reaction uses naturally abundant organic carboxylic acids as carbon sources,r eadily prepared azidoformates as the nitrogen sources,a nd 4-dimethylaminopyridine (DMAP) and Cu(OAc) 2 as catalysts with as lowa s 0.1 mol %loading, providing protected alkyl, alkenyl and aryl amines in high yields with gaseous N 2 and CO 2 as the only byproducts.E xamples are demonstrated of the late-stage functionalization of natural products and drug molecules, stereospecific synthesis of useful a-chiral alkyla mines,a nd rapid construction of different ureas and primary amines.

Breast cancer (BC) is the most frequently diagnosed type of cancer all over the world. Angiogenesis, a physiological or pathological process characterized by the sprouting of new blood vessels from existing vessels, plays a vital role in tumor nutrition. In this work, we used JSI-124 (Cucurbitacin I), a selective JAK/STAT3 signaling pathway inhibitor, to investigate the role of STAT3 in tumor angiogenesis of a human BC cell line in vitro. JSI-124 inhibited cell viability, proliferation, adhesion, migration and tube formation of a human BC cell line MDA-MB-468. After transfection with pMXs-Stat3C, a dominant active mutant, the inhibitory effects of JSI-124 on MDA-MB-468 were abolished. Furthermore, JSI-124 reduced the phosphorylation of STAT3. These results suggested that JSI-124 inhibited tumor angiogenesis of the human BC cell line in vitro through the reduction of STAT3 phosphorylation. In addition, JSI-124 could reduce VEGF transcription and secretion, suggesting that JSI-124 is also involved in the inhibition of the VEGF autocrine loop in the tumor microenvironment.