Here is the first visible light catalytic intermolecular cross [2 + 2] cycloaddition of enynes with alkenes to alkynyl cyclobutanes established with good functional group tolerance and high reaction efficiency and selectivity. Detailed studies reveal that enynes, including nonaromatic ones, can be sensitized by fac-Ir(ppy) 3 via an energy transfer pathway. Addition of the Lewis acid PPh 3 AuNTf 2 enables the cross photo[2 + 2] cycloaddition reaction to take place under both direct visible light irradiation or sensitization by Ru(bpy) 3 (PF 6 ) 2 .
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry