The regio- and stereoselectivity of the MCPBA-epoxidation of methyl dimorphecolate and derivatives

• Published in: Industrial crops and products Vol. 3; no. 4; pp. 273 - 280
• Main Authors: Tassignon, P., de Waard, P., de Wit, D., De Buyck, L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1995
• Subjects: 1H and 13C 2D NMR; 9-Acyloxy; 9-Methoxy; 9-Trimethylsiloxy; Agrotechnological Research Institute; benzoic acid; Conjugated dienes; derivatives; Dimorphotheca sinuata; fatty acids; Instituut voor Agrotechnologisch Onderzoek; m-chloroperbenzoic acid; Mono-oxiranes; organochlorine compounds; oxidation; stereochemistry; structure; 1H and 13C 2D NMR; Conjugated dienes; Mono-oxiranes; 9-Acyloxy; 9-Methoxy; 9-Trimethylsiloxy
• ISSN: 0926-6690; 1872-633X
• DOI: 10.1016/0926-6690(95)00011-Z

Methyl dimorphecolate (methyl 9(S)-hydroxy-10, 12-E,E-octadecadienoate) ( 1) was converted to resp. 9-methoxy ( 2), 9-trimethylsiloxy ( 3), 9-acetoxy ( 4), 9-chloroacetoxy ( 5) derivatives with reaction conditions optimized to high yields. The dienes were epoxidized with m-chloroperbenzoic acid to mono-oxiranes with excellent conversion (ratio C10–C11 epoxy to C12–C13: 90:10 for 9-hydroxy; 12:88 for 9-methoxy; 26:74 for 9-siloxy; 16:84 for 9-acetoxy; 17:83 for 9-chloroacetoxy). Methanolysis of a mixture of 9-chloroacetoxy oxiranes gave the 9-hydroxy mixture with 19:81 proportions of isomers. Analysis was based on 1H and 13C NMR-spectrometry including 2D techniques.