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

Abstract

The copper‐catalyzed highly selective protoboration of CF3‐containing conjugated diene with proton source and B2Pin2 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.

Nickel-Catalyzed anti-Markovnikov Hydroalkylation of Trifluoromethylalkenes

“…Along these lines, elegant works from the groups of Song and Cao demonstrated that a diversity-oriented elaboration could be achieved on the basis of Cu-catalyzed regiodivergent protoborylation of 2-trifluoromethyl-1,3-enynes. Zhang and co-workers extended these methods to protoborylation of trifluoromethyl-1,3-dienes . It is necessary to note that the suppression of defluorination in the examples above relied on the formation of stabilized propargyl- or allyl-copper intermediates that are less prone to undergo β-fluoride elimination.…”

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

“…The absolute configuration of 8f was measured by single crystal X-ray diffraction analysis of its 4-bromobenzoate ester. [17]…”

Catalytic Asymmetric Construction of CF3-Substituted Chiral sp3 Carbon Centers

“…Recently, Huang and Zhang reported the Cu/L17-catalyzed enantioselective protoboration of CF 3 -substituted 1,3dienes with pinB-Bpin and EtOH. 49 Electronically activated, aryl-substituted dienes were mainly employed, but successful application to the aliphatic substrate 63 was also shown (Scheme 22). After oxidative follow-up treatment of initially formed 64 with NaBO 3 •4H 2 O, the corresponding alcohol 65 bearing a chiral CF 3 -substituted sp 3 carbon center was obtained with good enantioselectivity.…”