Stereochemical control factors in the Hantzsch thiazole synthesis: a Hammett substitution correlation analysis.
[reaction--see text] It is possible to correlate the distribution of stereochemical products produced during a Hantzsch thiazole synthesis according to the Hammett free-energy equation. This analysis confirms the presumed control of the rate of epimerization during thiazole formation due to stabilization of a cationic transition state intermediate during dehydration of the thiazoline ring system. In the chemical system under study, the stereochemical outcome of the reaction also appears to occur according to a kinetically controlled protonation of a thiazoline tautomer.
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Roche Research Center, Nutley, New Jersey, 07110-1199, USA.
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Goodnow
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