An improved procedure for the Blaise reaction: a short, practical route to the key intermediates of the saxitoxin synthesis
Steven M. Hannick, Yoshito Kishi*
*Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, Email: kishichemistry.harvard.edu
S. M. Hannick, Y. Kishi, J. Org. Chem., 1983, 48, 3833-3835.
DOI: 10.1021/jo00169a053 (free Supporting Information)
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Slow addition of 3 - 5 eq. of α-bromo esters to aliphatic or aromatic nitriles in the presence of activated zinc in refluxing tetrahydrofuran yielded the corresponding enamino esters or, after acid hydrolysis, β-keto esters. Slow addition and use of tetrahydrofuran as solvent substantially improved the yield of the Blaise reaction and also enabled the conversion of bromoacetates to give α-unsubtituted products.
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