Photocatalytic Oxyalkynylation of Unactivated Alkenes Enabled by Hypervalent Iodine(III) Reagents

Abstract

The oxyalkynylation of alkenes offers a valuable strategy for constructing C−C and C−O bonds, generating βalkynyl alcohols frequently found in bioactive molecules. This work presents a photocatalytic approach for the oxyalkynylation of readily available unactivated alkenes using hypervalent iodine(III) reagents, acetoxylbenziodoxole (BI-OAc) and alkynylbenziodoxole (BI-alkyne), to afford anti-Markovnikov β-alkynyl alcohols. Mechanistic studies reveal a unique energy transfer process between BI-OAc and the photocatalyst, leading to the efficient generation of aryl carboxyl radicals. The aryl carboxyl radicals initiate atom-economical addition reactions with a broad range of commercially available mono-, di-, and trisubstituted alkenes, achieving anti-Markovnikov regioselectivity with BI-alkynes. The reaction can be readily scaled up to the gram scale, demonstrating its potential for late-stage modification of natural products and drug molecules. This method represents a significant advance in leveraging hypervalent iodine(III) reagents for radical generation and opens exciting avenues for future reaction design and development.