Enantioselective Synthesis of beta-Fluoro-beta-aryl-alpha-aminopentenamides by Organocatalytic [2,3]-Sigmatropic Rearrangement

摘要

The tetramisole-promoted catalytic enantioselective [2,3]-sigmatropic rearrangement of quaternary ammonium salts bearing a (Z)-3-fluoro-3-arylprop-2-ene group generates, after addition of benzylamine, a range of beta-fluoro-beta-aryl-alpha-aminopentenamides containing a stereogenic tertiary fluorine substituent. Cyclic and acyclic nitrogen substituents as well as various aromatic substituents are tolerated, giving the beta-fluoro-beta-aryl-alpha-aminopentenamide products in up to 76% yield, 96:4 dr, and 98:2 er.