Direct Photoexcitable Iodomethylborate Enabling Cyclopropanation of Reactive Alkenes

A radical-mediated cyclopropanation tool for reactive alkenes including dehydroamino acids (DHAAs) has been developed based on directly photoexcitable borate generating iodomethyl radical under visible light irradiation. The borate at the excited state serves as a strong single electron reductant. Therefore, this photoexcitable borate offers a simple protocol for cyclopropanation of DHAAs to forge medicinally-important cyclopropane amino acids. A radical-mediated cyclopropanation tool for reactive alkenes including dehydroamino acids (DHAAs) has been developed based on directly photoexcitable borate generating iodomethyl radical under visible light irradiation. The borate at the excited state serves as a strong single electron reductant. Therefore, this photoexcitable borate offers a simple protocol for cyclopropanation of DHAAs to forge medicinally-important cyclopropane amino acids.