Synthesis Of Multisubstituted Heterocyclic Compounds Via Propargyl Alkynol

Substituted Heterocyclic Compounds, such as furan, pyran, indole, pyridine and thiophene are "privileged structure", they are ubiquitous in natural products.These structures show strong physiological activity. Therefore, the development of more multisubstituted heterocyclic compounds makes very important significance.This paper mainly introduces two ways of the synthesis of multisubstituted benzo[b]furans via propargyl alkynol and phenols. Firstly, a one-pot cascade reaction for the synthesis of polysubstituted benzofurans from simple phenols and secondary propargylic alcohols is presented. The transformations are high yielding, atom-efficient, and environmentally benign in terms of the substrates and reagents being used. The control experiments support the transformations undergoing the sequence of propargylation, radical annulation and isomerization. Subsequently, we report anothcr cascade reaction for the synthesis of polysubstituted benzofurans from propargyl alcohol and phenols via [2+3] reaction model. Be different from existed reaction project by [3+3] reaction model to synthesize benzopyrans, this protocol displays a new path to construct benzofurans via tertiary propargyl alcohol with direacting group and phenols, proceeding allenylation, annulation. isomerization. This metal-free method with high yielding is easy to carry out and compatible to diverse functional groups.Finally, we have alse demonstrated that fully-substituted Spiro-oxazolidone and Spiro-benzopyrans could be synthesized efficiently via the metal-free-catalyzed one-pot cascade reaction from propargyl alkynol. New products are all confirmed by NMR and HRMS and some crucial structures are confirmed by X-ray.