Divergent Synthesis of Four Types of Fused N‐Containing Heterocycles via Oxidative Multi‐Component Cyclization Reaction

Comprehensive Summary An atmospheric‐oxygen‐mediated four‐component reaction was developed for the divergent synthesis of pyrazolo[1,5‐ a ]pyrimidine and pyrazolo[3,4‐ b ]pyridine derivatives from readily available alcohols and 3‐aminopyrazoles. In this transformation, atmospheric oxygen serves as the green oxidant, promoting alcohols as equivalent aldehydes for the synthesis of four types of N ‐containing heterocycles (> 40 examples). Remarkably, the transformation features metal‐free and molecular diversity.