A rapid and convergent synthesis of alpha,alpha-difluoro-beta-hydroxyketones through regiospecific defluorinative alkylation reaction

作者：Yanai Hikaru; Ichikawa Tatsunori; Taguchi Takeo^*

来源：Tetrahedron Letters, 2010, 51(19): 2625-2628.

DOI：10.1016/j.tetlet.2010.03.018

Both the defluorinative alkylation reaction of trifluoroacetaldehyde N,O-acetals using alkyllithiums and the following C-C bond formation with carbonyls as electrophiles were accelerated by a suitable diamine additive such as (-)-sparteine to give alpha,alpha-difluoro-beta-hydroxyketone N,O-acetal products in an excellent yield. We also found that N-benzyl-N,O-acetal group of the resultant products can be removed under palladium-catalyzed hydrogenolysis conditions giving rise to the corresponding alpha,alpha-difluoro-beta-hydroxyketones. The present two-step procedure is a useful and novel synthetic approach for functionalized alpha,alpha-difluoroketones.

• 出版日期2010-5-12