Related Experiment Video
Updated: Jun 16, 2026

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
Two versatile and parallel approaches to highly symmetrical open and closed natural product-based structures
Héctor E Montenegro1, Pedro Ramírez-López, María C de la Torre
1Instituto de Química Orgánica General, Consejo Superior de Investigaciones Científicas, Juan de la Cierva 3, 28006 Madrid, Spain.
Abstract:
Two parallel approaches for preparing diverse and highly symmetrical homohybrids derived from a series of mono- and diterpenes, steroids, and alkaloids are reported. Both procedures are based on the mono-addition of bis(alkynyl) dilithium reagents to natural products having a carbonyl group to produce the corresponding alkynyl derivatives. The Glaser-Hay Cu-promoted homocoupling of these alkynyl natural product mono-adducts as well as the Huisgen Cu-catalyzed azide-alkyne cycloaddition (CuAAC) reaction resulted in the synthesis of steroid-, terpene-, and alkaloid-based homohybrid derivatives incorporating diverse spacers to join the natural product scaffolds. Straightforward entries to novel closed highly symmetrical and complex estrone-based macrocyclic and cage architectures by means of the Glaser-Eglinton homocoupling and the CuAAC reaction have been devised.
Related Concept Videos
Stereoisomerism of Cyclic Compounds
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
Newman Projections
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as conformers.
Prochirality
Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...

