Rationally designed Fe-cyclopentadienone with unique orientations for efficient asymmetric hydrogenation of...

Area of Science:

• Organometallic Chemistry
• Asymmetric Catalysis
• Iron Chemistry

Background:

• Fe-cyclopentadienone complexes are vital in hydrogenation/dehydrogenation but lack efficient asymmetric applications.
• Chiral environment construction around the iron center is a significant challenge for asymmetric catalysis.

Purpose of the Study:

• To design and synthesize a novel chiral iron-cyclopentadienone complex for asymmetric catalysis.
• To evaluate its performance in asymmetric hydrogenation and transfer hydrogenation reactions.
• To investigate the structural features responsible for enantiocontrol.

Main Methods:

• Synthesis of a structurally distinct chiral Fe-cyclopentadienone complex.
• Catalytic asymmetric hydrogenation of various acylsilanes (aryl-, alkenyl-, alkyl-).
• Catalytic asymmetric transfer hydrogenation using isopropanol.
• Experimental and Density Functional Theory (DFT) studies.

Main Results:

• The new iron complex exhibits excellent enantiocontrol in acylsilane hydrogenation with high reactivity and selectivity.
• Broad substrate scope demonstrated, including aryl-, alkenyl-, and alkyl-acylsilanes.
• Successful gram-scale synthesis and catalyst stability confirmed.
• Effective asymmetric transfer hydrogenation achieved using isopropanol.
• Weak catalyst-substrate interactions identified as crucial for enantioselectivity.

Conclusions:

• A novel chiral iron complex with bulky side arms effectively creates a chiral environment for asymmetric catalysis.
• The catalyst demonstrates broad applicability and high performance in asymmetric hydrogenation and transfer hydrogenation.
• Structural rigidity and specific weak interactions are key to achieving high enantioselectivity in these iron-catalyzed reactions.