Photo-induced copper-catalyzed sequential 1,n-HAT enabling the formation of cyclobutanols

摘要

Cyclobutanols are difficult structures to access given their inherent ring strain. Here, the authors present a method to form substituted cyclobutanols from a photocatalytic cascade reaction, proceeding via a 1,5- or 1,6-hydrogen atom transfer and subsequent ring closure. @@@ Cyclobutanols are privileged cyclic skeletons in natural products and synthetic building blocks. C(sp3)-H functionalization is a prolonged challenge in organic synthesis. The synthesis of cyclobutanols through double C(sp3)-H bond functionalization remains elusive. Here we report the efficient synthesis of cyclobutanols through intermolecular radical [3 + 1] cascade cyclization, involving the functionalization of two C - H bonds through sequential hydrogen atom transfer. The copper complex reduces the iodomethylsilyl alcohols efficiently under blue-light irradiation to initiate the tandem transformation. The mild reaction tolerates a broad range of functional groups and allows for the facile generation of elaborate polycyclic structures.

关键词