Search for "metal-free oxidation" in Full Text gives 4 result(s) in Beilstein Journal of Organic Chemistry.
Beilstein J. Org. Chem. 2018, 14, 659–663, doi:10.3762/bjoc.14.53
Beilstein J. Org. Chem. 2016, 12, 1072–1078, doi:10.3762/bjoc.12.101
Beilstein J. Org. Chem. 2013, 9, 1296–1310, doi:10.3762/bjoc.9.146
Beilstein J. Org. Chem. 2013, 9, 602–607, doi:10.3762/bjoc.9.65