ABSTRACT
Alstonine and serpentine are pentacyclic indoloquinolizidine alkaloids (referred to as "anhydronium bases") containing three contiguous stereocenters. Each possesses interesting biological activity, with alstonine being the major component of a plant-based remedy to treat psychosis and other nervous system disorders. This work describes the enantioselective total syntheses of these natural products with a cooperative hydrogen bonding/enamine-catalyzed Michael addition as the key step.
Subject(s)
Amines/chemistry , Biological Products/chemical synthesis , Yohimbine/chemical synthesis , Biological Products/chemistry , Catalysis , Crystallography, X-Ray , Hydrogen Bonding , Models, Molecular , Molecular Structure , Stereoisomerism , Yohimbine/chemistryABSTRACT
An enantioselective Pd-catalyzed 6-endo-trig reaction for the synthesis of 2-aryl-chromenes has been developed. A systematic optimization of a TADDOL-derived ligand set resulted in the identification of a novel monodentate phosphoramidite-palladium catalyst that accesses 2-aryl-2H-chromenes with high yield and enantioselectivity under mild conditions. The products obtained from this method can be transformed into biologically active compounds through functionalization of the chromene alkene.
ABSTRACT
A series of 4,4'-ethynylenedibenzoic acids were synthesized and used in the construction of Zn-based, mixed-ligand metal-organic frameworks; through variation of functionality in the 3- and 3'-positions of these linkers, a collection of MOFs with differing connectivities and varying levels of interpenetration was obtained.
ABSTRACT
A highly active and selective Al-based catalytic Oppenauer (O) oxidation is reported. Quantitative and selective oxidations of a variety of benzylic, propargylic, allylic, and aliphatic primary and secondary alcohols were achieved using nitrobenzaldehyde derivatives as the oxidant and simple aluminum compounds as precatalysts.
