title: Catalytic enantioselective halolactonization of enynes and alkenes.
abstract: New organocatalysts have been developed for the enantioselective halolactonization of (Z)-1,3-enynes and 1,1-disubstituted alkenes. In the case of 1,3-enynes, the carboxylate nucleophile and halogen electrophile were added to the conjugated π-system from the same face. Up to 99% ee was achieved for the 1,4-syn-bromolactonization of conjugated (Z)-1,3-enynes. Based on the results from the enyne halolactonization, a second generation of catalysts was designed for simple olefins. Up to 91% ee was observed for chlorolactonization of 1,1-disubstituted alkenes. The catalysts developed for the enantioselective halolactonization of both enynes and alkenes are composed of a cinchona alkaloid skeleton tethered to a urea group.
authors.affiliation: The School of Pharmacy, University of Wisconsin, Madison, WI 53705-2222, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Na
authors.initials: N
authors.lastname: Liu
authors.forename: Casi M
authors.initials: CM
authors.lastname: Schienebeck
authors.forename: Kyle
authors.initials: K
authors.lastname: Decloux
authors.forename: Suqing
authors.initials: S
authors.lastname: Zheng
authors.forename: Jenny B
authors.initials: JB
authors.lastname: Werness
authors.forename: Weiping
authors.initials: W
authors.lastname: Tang
mesh_terms: D000466:Alkadienes / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D001966:Bromine / Q000737:chemistry*; D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D003500:Cyclization; D007783:Lactones / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D000466:Alkadienes; D000480:Alkynes; D007783:Lactones; D001966:Bromine