REACTION OF QUINOXALINES WITH β,γ-UNSATURATED GRIGNARD REAGENTS. SYNTHESIS OF ALLYL-, ALLENYL-, PROPARGYL-QUINOXALINE DERIVATIVES.

Article abstract of DOI:10.1016/S0040-4020(01)86883-6

Mono- and bis-addition reactions of the β,γ-unsaturated Grignard reagents 2 and 6 to the C=N bonds of quinoxalines 1 afford high yields of dihydroquinoxalines 4 and tetrahydroquinoxalines 3.Dehydrogenation of 4g-l and 3a-c with DDQ leads to allylic quinoxalines 1i-m and 1e-g respectively in very good yields.Allylic and propargylic quinoxalines 1m and 1s can conveniently be synthesized by "cross-coupling" of 2-chloro-3-methylquinoxaline with 2c and 6a.