Gold(III)-Catalyzed Propargylic Substitution Reaction Followed by Cycloisomerization for Synthesis of Poly-Substituted Furans from N-Tosylpropargyl Amines with 1,3-Dicarbonyl Compounds.

The treatment of N-tosylpropargyl amines 1 with 1,3-dicarbonyl compounds 2 in the presence of AuBr3 (5 mol%) and AgOTf (15 mol%) afforded poly-substituted furans 3 in good-to-high yields via the gold-catalyzed cleavage of the sp3 carbon-nitrogen bond.

Amurensiosides A-K, 11 new pregnane glycosides from the roots of Adonis amurensis.

Five new pregnane tetraglycosides, amurensiosides A-E (1-5), two new pregnane hexaglycosides, amurensiosides F (6) and I (9), two new 18-norpregnane hexaglycosides, amurensiosides G (7) and H (8), and two new pregnane octaglycosides, amurensiosides J (10) and K (11), were isolated from the MeOH extract of the roots of Adonis amurensis. The structures of the new compounds were determined on the basis of extensive spectroscopic analysis, including two-dimensional (2D) NMR data, and the results of hydrolytic cleavage. The isolated compounds were evaluated for their cytotoxic activity against HSC-2 human oral squamous cell carcinoma cells.