Enantioselective Total Syntheses of the Alkaloids (-)-Fortuneicyclidins A and B and (-)-Cephalotine B.

Fortuneicyclidins A and B are a pair of recently isolated alkaloids with an unprecedented rearranged polycyclic skeleton possessing multiple complex stereocenters and functionalization. In this work, highly stereocontrolled asymmetric total syntheses for title alkaloids were outlined. Key features include an underexplored Ir-catalyzed α-allylation of aldehyde to strategically install a vicinal N-substituted quaternary center and a tertiary stereocenter, Heck and RCM reactions to construct the critical polycyclic framework rapidly, two different tandem oxidation-transannular aldol cyclization processes, one through ozonolysis and another via Swern oxidation, to forge the last ring for fortuneicyclidins A and B, respectively.

Enantioselective Total Synthesis of the Alkaloid (-)-Cephalotine A.

Cephalotine A, a recently isolated Cephalotaxus alkaloid, was first synthesized enantioselectively through three critical reactions. SmI -mediated radical cyclization of lactone and aldehyde to forge the final ring system, Chang's iridium-catalyzed C-H amidation to construct pyrrolidone stereoselectively, and Carreria's dual Ir/amine catalyzed allylation to install the vicinal tertiary stereocenters.

Asymmetric Total Syntheses of (-)-Fennebricin A, (-)-Renieramycin J, (-)-Renieramycin G, (-)-Renieramycin M, and (-)- Jorunnamycin A via C-H Activation.

Collective total synthesis of five tetrahydroisoquinoline alkaloids including the first total synthesis of (-)-fennebricin A and (-)-renieramycin J has been accomplished. The synthesis features employing a single common amino acid to symmetrically construct the pentacycle of title alkaloids. The palladium-catalyzed arylation of alanine-derived amide developed by Yu was tactically utilized to afford unnatural amino acid building block rapidly and practically.

Selenium-lentinan inhibits tumor progression by regulating epithelial-mesenchymal transition.

Background: Selenium supplementation can be used to treat tumors. However, inorganic selenium is highly toxic, and natural organic selenium is extremely rare. Polysaccharides can improve drug bioavailability and targeting.

[Effect of Eu(Pr) substitution at Ba sites on microstructure and superconductivity in EuBa2Cu3O7-delta ceramics].

Ceramics of Eu1+xBa2-xCu3O7-delta with x = 0.0, 0.05, 0.