Chiral proton-transfer shuttle catalysts for carbene insertion reactions

Area of Science:

• Organic Chemistry
• Catalysis
• Asymmetric Synthesis

Background:

• Transition metal-catalyzed carbene insertion into X-H bonds is crucial in organic synthesis.
• Enantiocontrol in these reactions is challenging due to catalyst dissociation from active intermediates during proton transfer.
• Traditional chiral catalysts often fail to participate in the rate-determining proton transfer step.

Purpose of the Study:

• To develop efficient chiral catalysts for enantioselective carbene insertion reactions.
• To address the limitations of traditional catalysts in controlling proton transfer steps.
• To synthesize valuable chiral building blocks with high enantioselectivity.

Main Methods:

• Development of chiral spiro phosphoric acids (CPTS) as chiral proton-transfer shuttle catalysts.
• Combination of CPTS catalysts with achiral dirhodium catalysts.
• Application in carbene insertion reactions involving N-H, S-H, and C-H bonds.

Main Results:

• CPTS catalysts demonstrated high efficiency in facilitating proton transfer of active intermediates.
• The combined catalytic system achieved highly enantioselective insertions of N-H, S-H, and C-H bonds.
• Synthesis of diverse chiral building blocks, including α-amino acid derivatives and α-amino ketones, with excellent yields and enantioselectivities.

Conclusions:

• Chiral spiro phosphoric acids are effective chiral proton-transfer shuttle catalysts for carbene insertion reactions.
• The developed methodology provides a robust approach for enantioselective X-H bond functionalization.
• This strategy enables the efficient preparation of important chiral molecules for organic synthesis.