Simultaneous Construction of Planar and C-N Axial Chirality Ferrocenes by Pd-Catalyzed Cascade Reaction: Reciprocal
Congyu Gao1,2, Yuanyuan Liu1,2, Junpeng Liu1,2
1College of Chemistry & Chemical Engineering, Inner Mongolia University, Hohhot, 010021, China.
Abstract:
A Pd-catalyzed cascade combining asymmetric intramolecular C-H arylation and intermolecular Buchwald-Hartwig coupling constructs ferrocenes with both planar and C-N axial chirality (75% yield, 99% ee, 15:1 d.r.). Kinetic experiments and in situ 31P NMR confirmed the sequence of the cascade reactions. Moreover, this chirality stems from n-π* interactions and sterics. These ferrocenes are converted diastereoselectively (>20:1 dr) into planar/central chiral phosphine ligands. These ligands enable Pd-catalyzed enantioselective allylic alkylation (85% yield, 97% ee).
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