Chemoselectivity in Catalytic Transfer Hydrogenation — Reduction of Alkenes and Alkynes with the H₂PO₂^—NH₄⁺ · H₂O/Pd‐C System

Abstract

Abstract The H 2 PO 2 — NH 4 + · H 2 O/Pd‐C system acts as an unusually powerful reducing agent, which is able to reduce cyclooctene to cyclooctane, Δ 9,10 ‐octalin to decalins, α‐ and β‐pinenes to pinanes at room temperature in high yield without the formation of byproducts. This system selectively reduces each of these compounds or partly (alkynes to alkenes), depending on the competition between the transfer hydrogenation to give alkanes and the protonolysis to give hydrogen gas on the palladium catalyst.