Jie Marcel S F Lie Ken, Lam Corey N W
Department of Chemistry, The University of Hong Kong, Hong Kong, SAR, People's Republic of China.
Lipids. 2004 Jun;39(6):583-7. doi: 10.1007/s11745-004-1267-6.
The reaction of methyl 11,12-E-epoxy-9Z-octadecenoate (1) with boron trifluoride etherate furnished a mixture of methyl 12-oxo-10E-octadecenoate (3a) and methyl 11-oxo-9E-octadecenoate (3b) in 66% yield. Methyl 9,10-Z-epoxy-11E-octadecenoate (2) with boron trifluoride etherate furnished a mixture of methyl 9-oxo-10E-octadecenoate (4a, 45%) and methyl 10-oxo-11E-octadecenoate (4b, 19%). A plausible mechanism is proposed for these reactions, which involves the attack on the epoxy ring system by BF3, followed by deprotonation, oxo formation, and double bond migration to give a mixture of two positional alpha,beta-unsaturated C18 enone ester derivatives (3a/3b, 4a/4b). The structures of these C18 enone ester derivatives (3a/3b, 4a/4b) were identified by a combination of NMR spectroscopic and mass spectrometric analyses.
11,12-E-环氧-9Z-十八碳烯酸甲酯（1）与三氟化硼乙醚反应，以66%的产率得到12-氧代-10E-十八碳烯酸甲酯（3a）和11-氧代-9E-十八碳烯酸甲酯（3b）的混合物。9,10-Z-环氧-11E-十八碳烯酸甲酯（2）与三氟化硼乙醚反应，得到9-氧代-10E-十八碳烯酸甲酯（4a，45%）和10-氧代-11E-十八碳烯酸甲酯（4b，19%）的混合物。针对这些反应提出了一种合理的机理，该机理涉及BF3对环氧环体系的进攻，随后进行去质子化、羰基形成以及双键迁移，从而得到两种位置异构的α,β-不饱和C18烯酮酯衍生物（3a/3b，4a/4b）的混合物。通过核磁共振光谱分析和质谱分析相结合的方法确定了这些C18烯酮酯衍生物（3a/3b，4a/4b）的结构。
