A. Lubineau et al., REACTIVITY OF THE CARBONYL GROUP IN WATER - GENERATION OF AZOMETHINE YLIDES FROM AQUEOUS FORMALDEHYDE - MICHAEL ADDITION VERSUS DIPOLAR TRAPPING, Journal of the Chemical Society. Perkin transactions. I, (19), 1995, pp. 2433-2437
The ability of aqueous formaldehyde to generate azomethine ylides has
been studied. Treatment of methyl N-methylglycinate with dipolarophile
s in commercial aqueous formaldehyde gives pyrrolidines by azomethine
ylide cycloaddition which competes with a Michael addition.