Manganese‐Catalyzed Synthesis of Tetrahydropyridines via Borrowing Hydrogen Strategy

Tetrahydropyridines are versatile compounds widely used in organic synthesis and drug manufacturing. Herein, a manganese‐catalyzed borrowing hydrogen coupling of 1‐substituted ethanol derivatives with γ ‐amino alcohols is reported. This novel protocol has a broad substrate scope with good functional group tolerance and affords a diverse library of valuable 2,6‐disubstituted tetrahydropyridines in moderate to good yields. Mechanistically, the reaction proceeds sequentially through catalytic dehydrogenation, dual cross‐condensation, and further hydrogenation of the formed unsaturated intermediates to yield the desired tetrahydropyridines.