Ambiphilic Reactivity of SF5‐Alkynes Applied to Regioselective and Stereodivergent Halogenation Reactions: An Experimental and Theoretical Case Study

Abstract

We explored the ambiphilic reactivity of SF5‐alkynes, and we proved they can act as both nucleophiles and electrophiles. We selected halogenation reactions as benchmark reactions and developed highly selective stereodivergent hydrohalogenation (I, Br, Cl, F) reactions of SF5‐alkynes. The stereochemistry is finely controlled thanks to the nature of the acids used (strong or soft) in the presence of halide source, while the high regioselectivity is governed by the strong polarization of SF5‐alkynes. Mechanistic studies supported by DFT calculations shed light on two different reaction mechanisms responsible of the excellent stereocontrol. This stereoselectivity was quantitatively rationalized with the ASM and EDA methods. A few dihalogenation reactions are reported and DFT calculations rationalize this cis‐stereoselectivity. Relative configuration of all the SF5‐haloalkenes was unambiguously determined by X‐ray diffraction. Noteworthy, several post‐functionalization reactions such as cross‐couplings, cyanation and reductions are described to strengthen the synthetic potential.