One-Pot Zn/CuI/TFA-Catalyzed Domino Three-Component–Carbocyclization Reaction Involving Biphenyl-2-carbaldehydes/Alkynes/Piperidine: Allenes-Mediated Construction of Phenanthrenes
作者:Mohammad Saifuddin、Piyush K. Agarwal、Bijoy Kundu
DOI:10.1021/jo201942r
日期:2011.12.16
A one-pot protocol involving Zn/CuI/TFA-catalyzed domino three-component and subsequent carbocyclization reactions is described. The reaction proceeds via formation of propargyl amines from biphenyl-2-carbaldehydes/terminal alkynes/piperidine followed by the elimination of piperidine and ring closure to furnish phenanthrene derivatives in good yields. The strategy involves C(sp)-H activation-CH functionalization with imine-alkyne activation-1,5 hydride shift-beta-elimination of piperidine-allene formation-6 pi cycloaddition isomerization domino sequence. Evidence for the involvement of allenes as an intermediate during carbocyclization is discussed.