Methyltrioxorhenium (MTO)
Methyltrioxorhenium is commercial available and stable in air. MTO is an exceptionally versatile oxygen transfer catalyst with hydrogen peroxide as terminal oxidant. A drawback is the limited stability in water.
Recent Literature

A convenient and efficient oxidation of hydroxylated and methoxylated
benzaldehydes and acetophenones to the corresponding phenols uses hydrogen
peroxide and methyltrioxorhenium as catalyst in ionic liquids [bmim]BF4
and [bmim]PF6.
R. Bernini, A. Coratti, G. Provenzano, G. Fabrizi, D. Tofani, Tetrahedron, 2005,
61, 1821-1825.

Sodium percarbonate is an ideal and efficient oxygen source for the oxidation of
tertiary nitrogen compounds to N-oxides in excellent yields in the
presence of various rhenium-based catalysts under mild reaction conditions.
S. L. Jain, J. K. Joseph, B. Sain, Synlett, 2006,
2661-2663.

Sodium percarbonate is an ideal and efficient oxygen source for the oxidation of
tertiary nitrogen compounds to N-oxides in excellent yields in the
presence of various rhenium-based catalysts under mild reaction conditions.
S. L. Jain, J. K. Joseph, B. Sain, Synlett, 2006,
2661-2663.

A general, high yielding, and user and environmentally friendly catalytic
oxidation procedure for the chemoselective conversion of imines to nitrones is
reported.
G. Soldaini, F. Cardona, A. Goti, Org. Lett., 2007,
9, 473-476.
