A novel method is described for the introducing the 2, 2-dichloroethyl group at the 2- quinolone ring. The method from 4-substituted 2-quinolone consists of 1) photoaddition of the quinolone to 1, 1-dichloroethylene, 2) base treatment of the cross adduct giving a bicyclobutane, and 3) conversion of the latter to the final product with hydrogen chloride. By applying this reaction to 4-methoxy-2-quinolone, a short-step synthesis of dictamnine is ...
![1-chloro-7b-methoxy-1a,7b-dihydro-1,1a-methano-1H-cyclopropa[c]quinolin-2-(3H)-one Structure](https://image.chemsrc.com/caspic/368/111736-14-2.png)
![1,1-dichloro-8b-methoxy-1,2,2a,8b-tetrahydrocyclobuta[c]quinolin-3(4H)-one Structure](https://image.chemsrc.com/caspic/406/111736-13-1.png)