Disparate Catalytic Scaffolds for Atroposelective Cyclodehydration

Area of Science:

• Organic Chemistry
• Asymmetric Catalysis

Background:

• Stereocontrolled synthesis is crucial in chemistry.
• Privileged catalyst scaffolds are often generalized across reactions, but their mechanistic basis is unclear.
• Understanding catalyst scaffold uniqueness is key for broader applications.

Purpose of the Study:

• To investigate scaffold uniqueness in asymmetric catalysis.
• To compare C2-symmetric chiral phosphoric acids and peptidic phosphoric acids in atropisomer-selective cyclodehydration.
• To elucidate the mechanistic determinants of selectivity in these catalyst classes.

Main Methods:

• Utilized C2-symmetric chiral phosphoric acids and phosphothreonine-embedded peptidic phosphoric acids.
• Applied these catalysts to an unusual atropisomer-selective cyclodehydration reaction.
• Conducted mechanistic studies to differentiate selectivity determinants.

Main Results:

• Both catalyst scaffolds achieved high enantioselective and atroposelective cyclodehydrations.
• Mechanistic investigations revealed distinct factors governing selectivity for each catalyst type.
• A classification of asymmetric catalysts highlighted diverse chemotypes and mechanisms.

Conclusions:

• Catalyst scaffold uniqueness is demonstrated by differing mechanistic pathways leading to similar selectivity.
• Diverse catalyst chemotypes with distinct mechanistic features enable broad and complementary applications.
• This work expands opportunities for applying privileged catalyst scaffolds across various substrates.