Application of Cascade Reactions in the Synthesis of Sprio-heterocycles Initiated by Intramolecular Cyclization of Alkynols

Due to their unique stereoscopic structure and rich physical and chemical properties, spiro heterocyclic compounds have aroused the continuous attention of researchers on their efficient synthesis methods. The exo-cyclic enol ethers generated in situ by exo-dig cyclization of alkynols under the promotion of transition metals could serve as C2 synthons to react with various amphiphilic substrates through cascade reactions mode. These cascade reactions could afford spiro heterocyclic skeletons in highly efficient and direct manners. In this paper, the application progress of cascade reactions in the synthesis of sprio-heterocycles initiated by intramolecular cyclization of alkynols is reviewed, which aims to stimulate the disclosure of more related research work. These work is elaborated according to the different atom numbers of the amphiphilic substrates involved in the construction of the spiro framworks. The catalytic system and reaction mechanism are mainly described, the challenges in this field are analyzed, and the future development is also put forward.

Automated summary

This paper reviews the application progress of cascade reactions initiated by intramolecular cyclization of alkynols in the synthesis of spiro-heterocycles, aiming to highlight efficient methods for constructing these compounds. The analysis is based on the different atom numbers of substrates involved in building the spiro frameworks, describing catalytic systems, reaction mechanisms, challenges, and future directions in this field.