Delayed catalyst function enables direct enantioselective conversion of nitriles to NH₂-amines

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Enantiomerically enriched amines are crucial building blocks in pharmaceuticals.
• Current synthetic routes often involve multiple steps, increasing cost, waste, and limiting applicability.
• Nitriles are typically considered unreactive for direct functionalization into complex amines.

Purpose of the Study:

• To develop a direct, efficient, and cost-effective method for synthesizing multifunctional unprotected homoallylic amines from nitriles.
• To overcome the challenge of simultaneous competing catalysis for successful transformation.
• To demonstrate the utility of the developed method in synthesizing a complex pharmaceutical agent.

Main Methods:

• Enantioselective addition of a carbon nucleophile to a nitrile, forming a ketimine intermediate.
• Diastereodivergent reduction of the ketimine to yield the target amine.
• Simultaneous presence and controlled activation of competing copper-based catalysts using a nonproductive side cycle fueled by additives.

Main Results:

• Direct conversion of nitriles to unprotected homoallylic amines achieved.
• Successful implementation of simultaneous competing catalysis by delaying the more active catalyst.
• Demonstrated efficiency in the synthesis of the anticancer agent (+)-tangutorine.

Conclusions:

• The developed method offers a streamlined approach to enantiomerically enriched amines, reducing cost and waste.
• The strategy of controlled competing catalysis provides a new paradigm for complex synthetic challenges.
• This methodology significantly advances the synthesis of valuable amine-containing compounds, including pharmaceuticals.