Decarboxylative transamination. A new route to spirocyclic and bridgehead-nitrogen compounds. Relevance to α-amino acid decarboxylases

N-Substituted and α,α-disubstituted amino acids react with carbonyl compounds to generate 1,3-dipolar species under mild conditions mimicking α-amino acid decarboxylases; the 1,3-dipoles can be trapped both inter- and intra-molecularly to give bridgehead-nitrogen and spirocycli products in goood yield; pyridoxal is shown to react in an analogous fashion.