Stereoselective synthesis of perillaldehyde-based chiral β-amino acid derivatives through conjugate addition of lithium amides (original) (raw)
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Zeitschrift für Naturforschung B, 2014
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The Journal of Organic Chemistry, 1994
The alkylation of several enantiomerically pure perhydropyrimidin-4-ones a t C5 is described. For the methylation reaction, mixtures of 5,6-trans-and cis-disubstituted adducts were obtained with high diastereomeric ratios, whereas only the 5,6-trans-disubstituted products were obtained with larger alkylating agents. The dialkylation reaction a t C5 was also studied, and the 5,6-cistrisubstituted product was preferentially formed. Acidic hydrolysis of 5,6-trans-disubstituted perhydropyrimidin-4-ones furnished the corresponding p-amino acid hydrochlorides in quantitative yield. On cyclization of the amino acids, 5,6-trans-disubstituted azetidin-2-ones were also synthesized. @ Abstract published in Advance ACS Abstracts, November 1,1994. (1) See, for example: (a) Total and semi-synthetic approaches to Taxol. Tetrahedron 1992, 48, Symposia in Print no. 48, 6593. (b) Fredenhagen, A.; Tamura, S. Y.; Kenny, P. T. M.; Komura, H.; Naya, Y.; Nakanishi, K.; Nishiyama, K.; Sugiura, M.; E t a , H. J. Am. Chem. SOC. 1987, 109, 4409. (c) Konishi, M.; Nishio, M.; Saitoh, K.; Miyaki, T.; Oki, T.; Kawaguchi, H. (5) (a)Dkies, S. G.; Ganido, N. M.; Ichihara, 0.; Walters, I. A. S.