Interaction of 2,2'-bipyridine with allyl halides

In the reaction of 2,2'-bipyridine with allyl bromide and methallyl chloride in acetonitrile, bis-quaternary salts are formed: 1,1'-diallyl-2,2'-bipyridinium dibromide and 1,1'-bis(2-methallyl)-2,2'-bipyridinium dichloride. Thermal decomposition of dihalides leads to 5-(pyridin-2-yl)-1,8a-dihydroindolizine and 1,1',8a,8'a-tetrahydro-5,5'-biindolizine. During the alkaline hydrolysis of 1,1'-diallyl-2,2'-bipyridinium dibromide 1,1'-diallyl-6'-hydroxy-1',6'-dihydro-[2,2'-bipyridine]-6(1H)-one is formed.