NUK - logo
E-resources
Full text
Peer reviewed
  • Umpolung of Carbonyl Groups...
    Zhu, Dianhu; Lv, Leiyang; Li, Chen‐Chen; Ung, Sosthene; Gao, Jian; Li, Chao‐Jun

    Angewandte Chemie International Edition, December 10, 2018, Volume: 57, Issue: 50
    Journal Article

    Palladium‐catalyzed allylic alkylation of nonstabilized carbon nucleophiles is difficult and remains a major challenge. Reported here is a highly chemo‐ and regioselective direct palladium‐catalyzed C‐allylation of hydrazones, generated from carbonyls, as a source of umpolung unstabilized alkyl carbanions and surrogates of alkyl organometallic reagents. Contrary to classical allylation techniques, this umpolung reaction utilizes hydrazones prepared not only from aryl aldehydes but also from alkyl aldehydes and ketones as renewable feedstocks. This strategy complements the palladium‐catalyzed coupling of unstabilized nucleophiles with allylic electrophiles by providing an efficient and selective catalytic alternative to the traditional use of highly reactive alkyl organometallic reagents. Surrogates: A highly chemo‐ and regioselective direct palladium‐catalyzed C‐allylation of hydrazones was developed using umpolung carbonyls as a source of unstabilized alkyl carbanions and surrogates of highly reactive alkyl organometallic reagents. The method requires only a catalytic amount of both metal and ligand, delivers products in high yields, is easily scaled‐up, and demonstrates wide substrate scope and good functional‐group compatibility.