Palladium-catalyzed tandem reaction of 2-chloroquinoline-3-carbaldehydes and isocyanides.

A facile domino reaction of 2-chloroquinoline-3-carbaldehydes in one and two equivalents of isocyanide has been investigated. Three-component reactions of 2-chloroquinoline-3-carbaldehydes, isocyanides and amines are also described. In this Pd-catalyzed reaction under controlled conditions, three novel types of quinoline derivatives were formed via amidation, lactamization or carbamate formation along with the formation of C-C, C-N, and C-O bonds in a one-pot procedure.

Isocyanide Reactions Toward the Synthesis of 3-(Oxazol-5-yl)Quinoline-2-Carboxamides and 5-(2-Tosylquinolin-3-yl)Oxazole.

A palladium-catalyzed three-component reaction between 5-(2-chloroquinolin-3-yl) oxazoles, isocyanides, and water to yield 3-(oxazol-5-yl)quinoline-2-carboxamides is described. Interestingly, sulfonylation occurred when the same reaction was performed with toluenesulfonylmethyl isocyanide (TosMIC) as an isocyanide source. The reaction with 5-(2-chloroquinolin-3-yl)oxazoles and TosMIC in the presence of Cs2CO3 in DMSO afforded 5-(2-Tosylquinolin-3-yl)oxazoles. In basic media, TosMIC probably decomposed to generate Ts- species, which were replaced with Cl-. Tandem oxazole formation with subsequent sulfonylation of 2-chloroquinoline-3-carbaldehydes to form directly 5-(2-tosylquinolin-3-yl)oxazoles was also investigated.