Hydroesterification and difunctionalization of olefins with N-hydroxyphthalimide esters

Area of Science:

• Organic Chemistry
• Photochemistry
• Catalysis

Background:

• Hydroesterification is a valuable synthetic transformation for creating ester compounds.
• Developing mild and regioselective methods for hydroesterification remains an active area of research.
• Previous methods often require harsh conditions or lack control over regioselectivity.

Purpose of the Study:

• To develop a novel, mild, and regioselective hydroesterification method.
• To explore the use of N-hydroxyphthalimide aryl esters as acyl radical precursors.
• To investigate the scope and limitations of the developed methodology with various olefins.

Main Methods:

• Photochemical irradiation of N-hydroxyphthalimide aryl esters in the presence of unactivated olefins.
• Utilizing a facial tris(2-phenylpyridine)iridium(III) complex (fac-Ir(dFppy)3) as a photocatalyst.
• Employing dichloromethane (CH2Cl2) as the reaction solvent.

Main Results:

• Achieved mild and regioselective hydroesterification of terminal, 1,1-disubstituted, and trisubstituted olefins.
• Demonstrated anti-Markovnikov selectivity, consistent with alkyl radical intermediates.
• Observed formation of cyclized products from dienes and mono-acylated diols from substituted olefins in the presence of water.

Conclusions:

• The developed photocatalytic method provides an efficient route to various esters.
• The reaction proceeds via alkyl radical intermediates, offering control over regioselectivity.
• The methodology shows potential for synthesizing complex acylated molecules.