作者:Matthias Moens、Guido Verniest、Matthias De Schrijver、Peter ten Holte、Jan-Willem Thuring、Frederik Deroose、Norbert De Kimpe
DOI:10.1016/j.tet.2012.08.049
日期:2012.11
A strategy toward the synthesis of functionalized 5,5-difluoropiperidines, a class of compounds with potential as building block in medicinal chemistry, was developed. In a three-step procedure 2,2-difluoroglutaric anhydride was synthesized starting from ethyl bromodifluoroacetate. This key intermediate reacts fluently with various imines to yield 5,5-difluoropiperidinone carboxylic acids. Subsequent esterification of the obtained carboxylic acids enabled the isolation of trans-substituted 5,5difluoro-2-arylpiperidinone-3-carboxylates as the major isomers. Reduction of the difluorinated piperidinonecarboxylates using borane gave rise to new trans-2-aryl-1-benzyl-5,5-difluoro-3-hydroxymethylpiperidines in excellent yields. (C) 2012 Elsevier Ltd. All rights reserved.