Light, metal‐free regioselectiveC⁶‐Halkylation of purines and purine nucleosides with alcohols

Abstract

A metal‐, light‐free radical alkylation reaction of purines and nucleosides has been achieved with readily available alcohols (1°, 2°, 3°) as the alkyl radical sources enabled by oxalates, which does not need any catalysts, N2 protection, and protecting groups. Although there are three potential active C(sp2)H bonds and four interferential nitrogen atoms in the purine motif, the reaction still shows excellent regioselectivity at C6H position and does not face multialkylation problem. Besides, this approach shows broad functional groups tolerance and is scalable to the gram level, which can be applied to late‐stage CH alkylation of purine to synthesize 6‐cyclopentyl nebularine with anti‐CEM activity, thus demonstrating its utility.

Visible-Light-Driven Deoxygenative Heteroarylation of Alcohols with Heteroaryl Sulfones

“…In addition, the large excess of alcohols required and poor functional group tolerance in these methodologies hampered the expansion of the substrate scope. Overman reported the Minisci reaction of oxalate salts, but it requires stoichiometric amounts of peroxides and is only amenable for tertiary alcohols (Scheme C) . Therefore, the development of a mild, transition-metal-free, regioselective, and universal method for the deoxygenative heteroarylation of alcohols remains highly desirable.…”