Going to the source: Formamides or parentamines were used as an aminogroupsource for the silver‐mediated amination of benzoxazoles. Although reactions with formamides proceeded at high temperatures, the directamination with amines took place under much milder conditions (see scheme). Optically active aminogroups could also be installed without racemization.
Visible-Light-Triggered Oxidative C–H Aryloxylation of Phenolic Amidines; Photocatalytic Preparation of 2-Aminobenzoxazoles
作者:Vishnu Srivastava、Lal Yadav
DOI:10.1055/s-0033-1340150
日期:——
Visiblelight efficiently mediates an intramolecular cyclization reaction of o-hydroxy-N-aryl-N,N-dialkylformamidines (phenolic amidines) leading to 2-aminobenzoxazole derivatives in the presence of only 1 mol% tris(2,2′-bipyridine)ruthenium(II) as a photoredox catalyst along with air as terminal oxidant. The protocol involves oxidative functionalization of an amidinic C–H bond to a C–O bond and affords