Glyoxal intramolecular disproportionation

In view of the hydride-donating potential of (23), one might anticipate similar reactivity for adducts derived from, for example, amines and thiols. Intermolecular demonstrations of such reactivity are scarce on the other hand intramolecular examples are well known, although they may be mechanistically ambiguous. The prototype reaction is the intramolecular disproportionation of glyoxal (31) to glycolic acid (32), shown in equation (19). This reaction may be induced by hydroxide. With the aid of ab initio and MNDO-SCF-MO calculations a highly bent transition state has been calculated for hydride transfer. ... 

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