Hyponitrite precursor

A ready method for generating oxycaihinyl radicals for radical cyclization reactions involves adding di-/-butyl hyponitrite to refluxing solutions of precursors. For example the 6-bromide 26 gives a radical which is intramolecularly trapped by the nitrile group to pve an imine from which the product 27 is obtained on hydixdysis. ... 

This disproportionation requires N-N couphng chemistry in order to form the N2O product. Two intermediates are generally considered as plausible precursors to this reaction and subsequent product formation [12]. In form I (below), the metal center and corresponding hgand framework accommodate a ds-dinitrosyl species. In II, a hyponitrite (or hyponitrous) intermediate forms by electrophilic attack of NO onto a previously generated M-NO complex. 

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