The intramolecular Rauhut-Currier reaction creates a carbon-carbon bond between two tethered Michael acceptors. Previous asymmetric versions have relied on 1,4-additions of chiral nucleophilic catalysts. Herein, we investigate a novel strategy that involves the formation of electron rich dienamines as key intermediates. Our methodology provides an efficient entry to the iridoid framework.

Carbohydrate related enzymes, like glycosyltransferases and glycoside hydrolases, are nowadays more easily accessible and are thought to represent powerful and greener alternatives to conventional chemical glycosylation procedures. The knowledge of their corresponding mechanisms has already allowed the development of efficient biocatalysed syntheses of complex O-glycosides. These enzymes can al...

Three new minor iridoids were isolated from the roots of Scrophularia ningpoensis. They were elucidated as 8-Oferuloylharpagide, 8-O-(2-hydroxy-cinnamoyl)harpagide and 6-O-a-D-galactopyranosylharpagoside. # 1998 Published by Elsevier Science Ltd. All rights reserved.

From the leaves of Alangium kurzii, a new tetrahydroisoquinoline-monoterpene glucoside, 6-O-methyl-N-deacetylipecosidic acid and a new iridoid glucoside, 10-O-benzoyladoxosidic acid, were isolated along with alangiside, demethylalangiside, 6''-O-beta-D-glucosylhenryoside, uridine and four known flavonoid glycosides. The structures of new glucosides were determined on the basis of spectroscopic ...

Uridine diphosphate glycosyltransferases (UGTs) are pivotal in the process of glycosylation for decorating natural products with sugars. It is one of the versatile mechanisms in determining chemical complexity and diversity for the production of suite of pharmacologically active plant natural products. Picrorhiza kurrooa is a highly reputed medicinal herb known for its hepato-protective propert...

A few studies in the past have shown that plant diversity in terms of species richness and functional composition can modify plant defense chemistry. However, it is not yet clear to what extent genetic differentiation of plant chemotypes or phenotypic plasticity in response to diversity-induced variation in growth conditions or a combination of both is responsible for this pattern. We collected...