Dirhodium-Catalyzed Enantioselective Synthesis of Difluoromethylated Cyclopropanes via Enyne Cycloisomerization

Authors：Wang, Chuntao; Zhu, Dong; Wu, Rui^*; Zhu, Shifa^*

Source：Advanced Science, 2023.

DOI：10.1002/advs.202306404

• carbene
• cycloisomerization
• difluoromethylated cyclopropane
• dirhodium catalysis
• enantioselective synthesis

(Difluoromethylated cyclopropane represents an important motif, which is widely found in bioactive and functional molecules. Despite significant progress in modern chemistry, the atom-economic and enantioselective synthesis of difluoromethylated cyclopropanes is still challenging. Herein, an Rh2(II)-catalyzed asymmetric enyne cycloisomerization is described to construct chiral difluoromethylated cyclopropane derivatives with up to 99% yield and 99% ee in low catalyst loading (0.2 mol%), which can be easily transformed into highly functionalized difluoromethylated cyclopropanes with vicinal all-carbon quaternary stereocenters by ozonolysis. Mechanistic studies and the crystal structures of alkyne-dirhodium complexes reveal that the cooperative weak hydrogen bondings between the substrates and the dirhodium catalyst may play key roles in this reaction.) @@@ A Rh2(II)-catalyzed asymmetric enyne cycloisomerization to construct chiral difluoromethylated cyclopropane derivatives is reported, which can be easily transformed into highly functionalized difluoromethylated cyclopropanes with vicinal all-carbon quaternary stereocenters through ozonolysis. Mechanistic studies and the X-ray crystal structures of alkyne-dirhodium complexes reveal that the cooperative weak hydrogen bondings between the substrates and the dirhodium catalyst may play key roles in this reaction.image

• Institution
  南开大学