Phosphine-Catalyzed Annulation of Designed Enones and Ynones

The art of constructing complex molecular architectures has encouraged the generation of chemists to synthesize such molecules possessing significant biological and medicinal attributes. Inspired by the catalytic systems taking place in nature, chemists looked into imitating biocatalytic processes. This led to the birth of organocatalysis, where small organic molecules bearing minimal functionalities activate the substrate and affect the reactions. Organocatalysts are less toxic, readily available, and less sensitive towards air and moisture than metal catalysts.

Helped by intuition and persistence, organocatalysis has emerged as one of the most important frontiers in organic synthetic research and has become a powerful tool in constructing complex molecular skeletons. There are essentially four types of organocatalysts; Lewis bases, Lewis acids, Brønsted bases, and Brønsted acids. Among the Lewis bases, N-heterocyclic carbenes (NHCs), amines, and phosphines are widely employed in catalysis.
.