A NEW CHIRAL SYNTHESIS OF WIELAND-MIESCHER KETONE CATALYZED BY A COMBINATION OF (S)-N-BENZYL-N-(2-PYRROLIDINYLMETHYL)AMINE DERIVATIVE AND BRONSTED ACID

摘要

New or known N-benzyl-N-(2-pyrrolidinylmethyl)amine derivatives bearing a variety of substituents on the aromatic ring were easily prepared from N-Boc-proline or N-Boc-prolinol. The enantioselectivity of the intramolecular asymmetric aldol reaction mediated by a combination of the amine derivative and Bronsted acid to prepare Wieland-Miescher ketone was examined in detail. During the examination, remarkable substitutional effects on the aromatic ring were observed. Development of a catalytic version of the reaction was successfully achieved by the use of N-[(9-anthracenyl)methyl]-N-(2-pyrrolidinyl-methyl)amine in the presence of dichloroacetic acid.