Bifunctional catalyst promotes highly enantioselective bromolactonizations to generate stereogenic C-Br bonds.
A novel bifunctional catalyst derived from BINOL has been developed that promotes the highly enantioselective bromolactonizations of a number of structurally distinct unsaturated acids. Like some known catalysts, this catalyst promotes highly enantioselective bromolactonizations of 4- and 5-aryl-4-pentenoic acids, but it also catalyzes the highly enantioselective bromolactonizations of 5-alkyl-4(Z)-pentenoic acids. These reactions represent the first catalytic bromolactonizations of alkyl-substituted olefinic acids that proceed via 5-exo mode cyclizations to give lactones in which new carbon-bromine bonds are formed at a stereogenic center with high enantioselectivity. We also disclose the first catalytic desymmetrization of a prochiral dienoic acid by enantioselective bromolactonization.
Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712, USA.
Daniel H
DH
Paull
Chao
C
Fang
James R
JR
Donald
Andrew D
AD
Pansick
Stephen F
SF
Martin
D000475:Alkenes / Q000737:chemistry*; D001966:Bromine / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry*; D002384:Catalysis; D054879:Halogenation; D007783:Lactones / Q000737:chemistry*; D009284:Naphthols / Q000737:chemistry; D013237:Stereoisomerism
D000475:Alkenes; C406944:BINOL, naphthol; D002264:Carboxylic Acids; D007783:Lactones; D009284:Naphthols; D001966:Bromine