Catalyst-Free Visible Light Mediated Synthesis of Unsymmetrical Tertiary Arylphosphines

Arylation of tertiary aryl and alkyl phosphines bearing 2-cyanoethyl group with aryl(mesityl)iodonium triflates under blue light irradiation followed by retro-Michael reaction of the in situ generated quaternary phosphonium salts initiated by DBU represent a novel efficient and general method for the preparation of distinctly substituted tertiary arylphosphines. An operationally simple, one-pot protocol features mild, transition-metal-free conditions, high selectivity, broad functional group compatibility, as well as scalability and would be applied to substrates with different electronic and steric nature.

Automated summary

This study presents a simple and efficient method for the preparation of highly substituted tertiary arylphosphines. The method involves the arylation of tertiary aryl and alkyl phosphines with aryl(mesityl)iodonium triflates under blue light irradiation, followed by a retro-Michael reaction initiated by DBU. The method is mild, transition-metal-free, and shows high selectivity, broad functional group compatibility, as well as scalability and applicability to substrates with different electronic and steric nature.