Hammick reaction

The Hammick reaction is a chemical reaction described as a thermal decarboxylation of α-picolinic (or related) acids in the presence of carbonyl compounds to form 2-pyridyl-carbinols.^[1][2]

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Using p-cymene as solvent has been shown to increase yields.^[3]

Reaction mechanism

Upon heating α-picolinic acid will spontaneously decarboxylate forming a zwitterion (2). In the presence of a strong electrophile, such as an aldehyde, the zwitterion will react with the carbonyl faster than protonating. Upon proton transfer the desired carbinol (4) is formed.

References

1. ^  (a) Dyson, P.; Hammick, D. L. J. Chem. Soc. 1937, 1724. (b) Hammick, D. L.; Dyson, P. J. Chem. Soc. 1939, 809.
2. ^  Brown, E. V.; Shambhu, M. B. J. Org. Chem. 1971, 36, 2002. (doi:10.1021/jo00813a034)
3. ^  Sperber, N.; Papa, D.; Schwenk, E.; Sherlock, M. J. Am. Chem. Soc. 1949, 71, 887.