Deepak M. Shendage, R. Froehlich, K. Bergander
Feb 1, 2005
Citations
0
Influential Citations
19
Citations
Journal
ChemInform
Abstract
Asymmetric alkylation of (S)-Boc-BMI (1a, BMI = 2-tert-butyl-3-methylimidazolidin-4-one) and its α-methyl derivative 1b with 2-fluoroallyl tosylate, subsequent mild acidic deprotection of the products 2a and 2b, and basic hydrolysis of the thus formed N-methylamides 4a and 4b gave (S)-2-amino-4-fluoropent-4-enoic acid (5a) and (S)-2-amino-4-fluoro-2-methylpent-4-enoic acid (5b). Basic hydrolysis of compound 4a was accompanied by partial racemization, which was overcome by applying a new stereoconservative deamidation procedure. The alkylated cis-configured product 2a formed under kinetic control epimerized on refluxing with 2 n NaOH to give the thermodynamically more stable trans isomer 9. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)