Synthesis of polyallenoates through copper-mediated cross-coupling of dialkynes and bis-α-diazoesters.

The copper-catalyzed cross-coupling of alkynes and α-diazoesters has been applied in the synthesis of polyallenoates for the first time. The polymerization tolerated various functional groups and afforded the polyallenoates with high molecular weight. With chiral guanidinium bromide as a ligand, the axial chirality of the allene moiety could be generated with high enantioselectivity during the polymerization process.

The Generation of Difluoroketenimine and Its Application in the Synthesis of α,α-Difluoro-ß-amino Amides.

Fluorine-containing ß-amino acids and their derivatives have attracted significant attention due to their importance in life sciences. Herein the previously unknown difluoroketenimine, the analogue of the elusive difluoroketene, has been generated by the reaction of difluorocarbene and isocyanide, which further undergoes [2+2] cycloaddition with imine. The three-component reaction affords α,α-difluoro-ß-amino amides in good yields. Mechanistic studies reveal the unique properties of the difluoroketenimine in the [2+2] cycloaddition with imine.