Nickel(II)‐Catalyzed Selective (E)‐Olefination of Methyl Heteroarenes Using Benzyl Alcohols via Acceptorless Dehydrogenative Coupling Reaction.

An efficient catalytic protocol for the synthesis of selective (E)‐olefins by the newly synthesized nickel complexes via greener acceptorless dehydrogenative coupling methodology is presented. Two nickel(II) N, S chelating complexes were structurally characterized with the aid of spectral and single crystal X‐ray diffraction methods. Olefination of 2‐methylheteroarenes with benzyl alcohols via acceptorless dehydrogenative coupling is achieved by inexpensive nickel(II) catalysts. The present olefination protocol is simple and furnishes the desired 2‐alkenylheteroarenes in 35 h and yields in the range of 40–93 %. The dehydrogenative coupling reaction proceeds via the generation of an aldehyde intermediate and produces water and hydrogen as sole by‐products. The wide substrate scope of this catalytic reaction covered the synthesis of drug intermediates. [ABSTRACT FROM AUTHOR]

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