Binuclear Ruthenium (II) Catalyzed Selective α‐Alkenylation of Amide via Acceptorless Dehydrogenative Coupling of Alcohols

ABSTRACT Herein, we report an effective catalytic methodology for the construction of α , β ‐unsaturated amides via acceptorless dehydrogenative coupling (ADC) of alcohols using newly synthesized binuclear ruthenium (II) complex ( η 6 ‐p‐cymene) 2 Ru 2 Cl 2 (μ‐L) (where L = N ′‐4‐fluoro benzoyl‐4‐fluorobenzohydrazide) as catalyst. The structural characterization of the newly synthesized ruthenium complex has been established using analytical and various spectroscopic techniques (FT‐IR, UV–vis, and NMR). Further, the molecular structure of the complex has been authenticated by a single‐crystal X‐ray diffraction method. The catalytic system displaces a wide range of α , β ‐unsaturated amides (16 examples), which have been obtained from the reaction of diverse primary alcohols and aryl amide with maximum of 93% of yield. The protocol for α‐alkenylation of amide involves through C‐C bond formation utilizing 0.5 mol% of catalyst loading with the release of release water and hydrogen gas as the only by‐products. The control experiments evidence the initial dehydrogenation of alcohols into their corresponding aldehydes and C=C bond formation through aldol condensation. In addition, a large‐scale synthesis of one of the amides (E)‐3‐(4‐methoxyphenyl)‐N‐phenyl acrylamide has been performed with the yield of 78%, which proves the effectiveness of the present catalytic protocol.