Unlike methyl groups, it can commonly undergo transannular migration; such migrations involve a two- electron transition state.
One of these is transferred between two aldehyde molecules in the Canizzaro reaction. Metals in groups 7 to 9 form few stable molecules with it, but some compounds that it does form with metals are used to synthesize aldehydes from imidazoles and amines from oximes. Affinity for it is commonly used as a measure of gas phase carbocation stability. Unlike methyl groups, it can commonly undergo transannular migration; such migrations involve a two- electron transition state. A source of reducing equivalents in a compound with sodium and boron, or with lithium and aluminum, for ten points, identify this chemical entity that consists of two electrons and a proton.
One of these is transferred between two aldehyde molecules in the Canizzaro reaction.
{hydride} anion (prompt on “hydrogen”)