A facile two-step synthesis of (ω-1)-fluoroalkan-ω-olides influence of a vicinal fluorine substituent in nucleophilic substitutions
作者:Andreas Sattler、Günter Haufe
DOI:10.1016/0040-4020(96)00182-2
日期:1996.4
(ω-1)-Fluoroalkan-ω-olides 3 of medium to garge ring size can easily be synthesised in a facile two-step procedure by bromofluorination of terminally unsaturated fatty acids 1 with NBS/Et3N·3HF and subsequent cyclisation with K2CO3 in dimethyl sulfoxide. Electronic and conformational changes induced by the vicinal fluorine substituent in the transition state of SN2-cyclisation step (calculated by the
中等大小的(ω-1)-氟代烷烃-ω-内酯3可以轻松地通过两步程序轻松合成,方法是将末端不饱和脂肪酸1与NBS / Et 3 N·3HF进行溴氟化,然后与K环合二甲亚砜中的2 CO 3。发现在S N 2环化步骤的过渡态中,邻位氟取代基引起的电子和构象变化(由AM1-方法计算)与单氟化化合物2的非环化相比,肯定阻碍了单氟化化合物2的环化。氟化类似物。