Cross-Coupling Reactions between Alkenes by C-H Cyclometalation

Alkenes are one of the most abundant raw feedstocks and are utilized to construct complex chemicals, whilst cross-coupling reactions using alkenes represents a powerful method toward valuable chemicals. In the past decade, cross-coupling reactions of simple alkenes by chelation-assisted alkenyl C-H functionalization has attracted significant attention due to its atom/step efficiency and excellent Z/E selectivity, proceeding by C-H exo-cyclometalation and endo-cyclometalation. In this account, we summarize transition-metal-catalyzed cross-coupling reactions between alkenes to generate 1,3-dienes via C- H alkenylation,1,4-dienes through C-H allylation, multisubstituted alkenes via hydroalkenylation, and heterocycles by way of tandem alkenyl C-H functionalization/annulation. Asymmetric alkenyl C-H alkenylation to prepare axially chiral aryl 1,3-dienes is also discussed.1 Introduction2 Alkenyl C-H Alkenylation2.1 By endo-Cyclometalation2.2 By exo-Cyclometalation3 Alkenyl C-H Allylation3.1 By endo-Cyclometalation3.2 By exo-Cyclometalation4 Alkenyl C-H Alkylation via Hydroalkenylation5 Cascade Reactions6 Conclusion