Photoinduced Dearomatizing Three-Component Coupling of Arylphosphines, Alkenes, and Water.

A unique photoinduced reaction that couples a triarylphosphine, an alkene, and water to produce 2-(cyclohexa-2,5-dienyl)ethylphosphine oxide is reported herein. The alkene inserts into a C(aryl)-P bond of the arylphosphine, the aryl ring is dearomatized into the cyclohexadienyl ring, and the phosphorus is oxidized. The three components are all readily available, and their intermolecular coupling significantly increases molecular complexity. The products formed are applicable to the Wittig olefination.