Mechanistic study on a unique SN2′-type reaction of allylic alcohols with organolithium reagent accelerated by a proximal trifluoromethyl group

• Structure–reactivity-relationship study of this reaction was investigated.
• Chelation of alkoxide and fluorine to the lithium ion plays a crucial role.
• Theoretical investigation was examined for supporting the proposed mechanism.

We previously found that treatment of (Z)-trifluoromethylated-2-aryl allylic alcohols with organolithium provided the SN2′-type product through CO bond cleavage. Interestingly, no additive was required to enhance the nucleophilicity of the organolithium, and the free hydroxyl group served as a leaving group. The mechanistic studies of the unique transformation indicated that chelation of alkoxide and fluorine of the trifluoromethyl group to the lithium ion play a crucial role in controlling the reactivity and selectivity. Furthermore, theoretical investigation supported this interpretation.

Mechanistic study on SN2′-type reaction of (Z)-trifluoromethylated allylic alcohol with organolithium reagent was examined.Figure optionsDownload as PowerPoint slide