Palladium-catalyzedmonofluoromethylation of substituted 2-bromo-1,3-dienes using fluorobis(phenylsulfonyl)methane (FBSM) as a pronucleophile gave previously unknown monofluoromethylated allenes in high yields, which are the isosteres of biologically attractive allenic alcohols.
Palladium-catalyzed reactions of various 2-bromo-3-exo-methylenecycloalkenes with a stabilized nucleophile were examined. When the carbocycles were nine-membered or larger, the corresponding endocyclic allenes were isolated in excellent yields. In a reaction of the eight-membered cyclic substrate, initial formation of a cycloocta-1,2-diene derivative was detected; however, it dimerized slowly. The