C-H amination reactions inside α-cyclodextrin supramolecular capsule

Area of Science:

• Supramolecular Chemistry
• Photochemistry
• Organic Synthesis

Background:

• Supramolecular capsules offer controlled environments for chemical reactions.
• Nitrene intermediates are highly reactive species used in functionalization reactions.
• C-H amination is a key transformation in organic synthesis.

Purpose of the Study:

• To describe the photochemical generation of an alkoxycarbonylnitrene within a supramolecular capsule.
• To investigate the reactivity and selectivity of the generated nitrene species.
• To elucidate the mechanism of C-H amination facilitated by the supramolecular assembly.

Main Methods:

• Co-crystallization of 2-adamantyl-carbonazidate within an alpha-cyclodextrin (α-CD) capsule.
• Photochemical irradiation (UV light, 254 nm) in solid state and suspension.
• Analysis of reaction products to determine C-H amination sites and minor product formation.

Main Results:

• Photochemical generation of an alkoxycarbonylnitrene inside the α-CD capsule upon UV irradiation.
• Selective C-H amination of the α-CD capsule wall at the C5 position.
• Mimicking of the transition state geometry for triplet nitrene H-atom abstraction by the supramolecular assembly.
• Concomitant enantioselective intramolecular carbamate formation, providing mechanistic insights.

Conclusions:

• Supramolecular capsules can effectively host and control reactive nitrene intermediates.
• The study demonstrates a novel method for selective C-H amination within a confined supramolecular environment.
• The findings offer valuable mechanistic understanding of nitrene-mediated C-H functionalization reactions.