Copper-Catalyzed Highly Selective Protoboration of CF3-Containing 1,3-Dienes

The copper-catalyzed highly selective protoboration of CF3-containing conjugated diene with proton source and B(2)Pin(2) has been developed. This chemistry could suppress the well-known defluorination and provide borated reagents with an intact CF3-group. Further studies indicated that the functional group tolerance of this chemistry is very well, and the products could be used as versatile precursors for different types of transformations. Importantly, using chiral diphosphine ligand, we have developed the first example for using such starting material to synthesis allylic boron-reagents which bearing a CF3-containing chiral center. Notably, the reaction mechanism was intensively studied by DFT calculations, which could reveal the reason that defluorination was inhibited.

Automated summary

The study presents a copper-catalyzed highly selective protoboration reaction that can suppress defluorination and provide CF3-containing borated reagents. Functional group tolerance of this reaction is well demonstrated, with the products serving as versatile precursors for various transformations. By using a chiral diphosphine ligand, allylic boron reagents with a CF3-containing chiral center were synthesized for the first time. Additionally, in-depth DFT calculations were conducted to understand the mechanism behind the inhibition of defluorination.