Organocatalytic Enantioselective Fluorocyclizations
19 October 2011 (online)
The Scheme of this article contained an incorrect alkaloid structure. The correct structure is shown below. Further, the interpretation of the mechanism, ‘According to NMR studies, it is the N-fluoroammonium salt of the alkaloid which may be responsible for the enantiocontrol in the reaction’ may mislead the readers. While this appears to be valid in the stoichiometric process, the catalytic variant presumably has a different mechanistic regime. The authors found at the reaction temperature of -78 ˚C, (DHQ)2PHAL was not fluorinated. Therefore, in the catalytic fluorocyclizations (conditions B), associative complexation of the alkaloid with the substrate, for example through hydrogen bonding with the pendant nucleophile, might be the origin of enantioinduction.