Science of Synthesis

Yamazaki, T., Science of Synthesis Knowledge Updates, (2017) 2, 287.

Allylic bromides can also be used as electrophiles with appropriate nucleophiles, for which SN2 and SN2′ pathways basically compete. In the case of γ-fluoromethylated allyl bromides, complete SN2′ preference is observed by treatment with a variety of Grignard reagents under the action of a catalytic amount of N-heterocyclic carbene ligand ‌19‌ (‌Scheme 10‌); the reaction usually provides products ‌20‌ with excellent enantiomeric excess values.[‌15‌]

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References