Ruthenium-Catalyzed Synthesis of 2-Pyrazolines via Acceptorless Dehydrogenative Coupling of Allylic Alcohols with Hydrazines

Abstract

Described herein is the synthesis of 2-pyrazolines via acceptorless dehydrogenative coupling of allylic alcohols with hydrazines based on a Ru₃(CO)₁₂/NHC-phosphine-phosphine ligand L catalytic system. The reaction not only exhibits low catalyst loading (only 0.3 mol %), wide substrate scope, good to excellent yields, and high selectivity but also omits the use of sacrificial hydrogen acceptor with only H₂ and H₂O as byproducts, making the reaction green and atom-economical.