Four-carbon homologating agents are important in many syntheses. The acetals of 4- halobutanah have been used as alkylating agents to extend molecules by four carbons, while providing an aldehyde function at the new terminus. They have also been converted to Grignard and organolithium reagents and used to prepare 1, bdifunctionality. 1, l-Diethoxy-4- halobutanes' and 2-(3-halopropyl)-l, 3-di-oxolanes, lb, 4 and l~,~ have seen frequent use. ...
