Treatment of acyl chlorides and diaryl ketones with an activated Ti(o)reagent,prepared by reduction of TiCl_4 with Zn powder,effects an intermolecular reductive cross-coupling reaction leading to ketones.
The deprotonative functionalization of toluenes,for their weak acidity,generally needs strong bases,thus leading to the requirement of harsh conditions and the generation of by-products.Direct nucleophilic acyl substi...The deprotonative functionalization of toluenes,for their weak acidity,generally needs strong bases,thus leading to the requirement of harsh conditions and the generation of by-products.Direct nucleophilic acyl substitution reaction of amides with organometallic reagents could provide an ideal solution for ketone synthesis.However,the inert amides and highly reactive organometallic reagents bring great challenges for an efficient and selective synthetic approach.Herein,we reported an lithium diisopropylamide(LDA)-promoted benzylic aroylation of toluenes with unactivated tertiary benzamides,providing a direct and efficient synthesis of various aryl benzyl ketones.This process features a kinetic deprotonative functionalization of toluenes with a readily available base LDA.Mechanism studies revealed that the directed ortho-lithiation of the tertiary benzamide with LDA promoted the benzylic kinetic deprotonation of toluene and triggered the nucleophilic acyl substitution reaction with the amide.展开更多
文摘Treatment of acyl chlorides and diaryl ketones with an activated Ti(o)reagent,prepared by reduction of TiCl_4 with Zn powder,effects an intermolecular reductive cross-coupling reaction leading to ketones.
基金This work was supported by the Natural Science Foundation of Tianjin(19JCYBJC20100).
文摘The deprotonative functionalization of toluenes,for their weak acidity,generally needs strong bases,thus leading to the requirement of harsh conditions and the generation of by-products.Direct nucleophilic acyl substitution reaction of amides with organometallic reagents could provide an ideal solution for ketone synthesis.However,the inert amides and highly reactive organometallic reagents bring great challenges for an efficient and selective synthetic approach.Herein,we reported an lithium diisopropylamide(LDA)-promoted benzylic aroylation of toluenes with unactivated tertiary benzamides,providing a direct and efficient synthesis of various aryl benzyl ketones.This process features a kinetic deprotonative functionalization of toluenes with a readily available base LDA.Mechanism studies revealed that the directed ortho-lithiation of the tertiary benzamide with LDA promoted the benzylic kinetic deprotonation of toluene and triggered the nucleophilic acyl substitution reaction with the amide.
