Cascade reactions to 2,4-disubstituted thiazoles via ligand-free palladium(II)-catalyzed C(sp)–C(sp2) coupling

A simple construction for various 2,4-disubstituted thiazoles via palladium(II)-catalyzed C(sp)–C(sp2) and C-N cascade coupling reactions was developed. Various substrates can be tolerated with good yields. And its ligand-free condition demonstrates the practicability of this method. [Display omitted] •A simple construction for various 2,4-disubstituted thiazoles.•The reaction involves C(sp)–C(sp2) coupling followed by intramolecular C–N bond formation.•Various substrates can be tolerated with good yields in ligand-free condition.