Asymmetric Propargylic C−C Bond Formation Using Metal–Allenylidene Species

Abstract

AbstractThe alkyne group is the key component of many bioactive molecules and versatile synthetic building block, thus the introduction of which into target molecules has attracted considerable interest from scientists. Moreover, tertiary and quaternary stereocenters are common motifs in natural products and drugs, however, the asymmetric construction of such motifs is one of the challenging tasks due to the steric congestion of multiple stereospecific substituents attached to one carbon. Metal–allenylidene are an excellent type of electrophilic species. The asymmetric addition of carbon‐nucleophiles at Cγ of the metal–allenylidene provides an effective way to construct tertiary and quaternary stereocenters as well as to introduce an alkyne group. In this review, the state‐of‐the‐art asymmetric propargylic C−C bond formation via metal‐allenylidene generated in situ from propargylic alcohol derivatives are presented. Synthetic applications, mechanistic insights are addressed. The challenges and opportunities of this field are also discussed.