Photochemical Nozaki-Hiyama-Kishi Coupling Enabled by Excited Hantzsch Ester.

This work reports the first photochemical Nozaki-Hiyama-Kishi coupling enabled by bioinspired Hantzsch ester. The salient feature of this process is that commercially available and low-cost organic photoactive Hantzsch ester can serve as both an electron and a proton donor to reduce Cr/Ni to low-valent species and hydrolyze the CrIII-alkoxy bond, thus bypassing the use of stoichiometric metallic reductants and additives such as TMSCl and Cp2ZrCl2. The mild conditions and operationally easy method showed broad compatibility with various alkenyl triflates and aldehydes, including electron-poor pentafluorobenzaldehyde which failed under previous conditions.