Stereoselective Transesterification of P-Chirogenic Hydroxybinaphthyl Phosphinates

Area of Science:

• Organic Chemistry
• Asymmetric Synthesis
• Organophosphorus Chemistry

Background:

• P-chirogenic compounds are crucial building blocks in medicinal chemistry and asymmetric catalysis.
• Developing efficient methods for synthesizing enantiomerically pure P-chirogenic phosphinates remains a significant challenge.

Purpose of the Study:

• To develop a novel, efficient, and selective substitution reaction for the synthesis of P-chirogenic phosphinates.
• To explore the scope and limitations of the reaction using various alcohols and substituted phosphinate substrates.
• To demonstrate the utility of the synthesized compounds in preparing a drug candidate for Duchenne muscular dystrophy.

Main Methods:

• Substitution reaction of phosphinates bearing a binaphthyloxy group with lithium alkoxides.
• Utilizing primary, secondary, and tertiary alcohols, including tert-butyl alcohol.
• Employing substrates with diverse alkyl groups on the phosphorus atom.
• X-ray crystallographic analysis to determine molecular structures and stereochemistry.
• Thionation of phosphinates to yield phosphinothioates.

Main Results:

• The substitution reaction proceeded with good to high efficiency, yielding P-chirogenic phosphinates with high enantiomeric ratios.
• A broad range of alcohols (primary, secondary, tertiary) were successfully employed, with tert-butyl alcohol affording superior enantioselectivity.
• Substrates with two different alkyl groups exhibited excellent selectivity, providing corresponding products in good yields.
• X-ray analysis confirmed the substitution proceeds with inversion of absolute configuration at the phosphorus center.
• The reaction was successfully applied to synthesize a drug candidate for Duchenne muscular dystrophy.
• Thionation of the resulting phosphinates efficiently produced P-chirogenic phosphinothioates.

Conclusions:

• A highly efficient and enantioselective method for synthesizing P-chirogenic phosphinates has been established.
• The reaction demonstrates broad substrate scope and high selectivity, making it a valuable tool in asymmetric synthesis.
• The developed methodology provides a viable route for the preparation of pharmaceutically relevant compounds, including Duchenne muscular dystrophy drug candidates.