Regio‐ and Stereoselective Hydroelementation of SF₅‐Alkynes and Further Functionalizations.

Abstract

Herein is described a fully regio-and stereoselective hydroelementation reaction of SF 5 -alkynes with N, O and S-nucleophiles and further functionalization of the corresponding Z-(hetero)vinyl-SF 5 intermediates, a suitable platform to access α-SF 5 ketones and esters, β-SF 5 amines and alcohols under mild reaction conditions. Experimental and computational comparative studies between SF 5 -and CF 3 -alkynes have been performed to highlight and explain the difference of reactivity and selectivity observed between these two fluorinated motifs.

Organocatalytic hydration of activated alkynes

“…We next sought to identify possible reaction intermediates. Considering that the addition of sulfides to alkynes is well-documented, (15,40,41) we hypothesised that the initial step involves the addition of cysteine to the triple bond via the thiolate moiety, which is consistent 15 with the pH dependency observed during the reaction optimisation studies (Table S3). We next probed the role of both acid and amino groups in the mechanism (Fig 4A).…”

Regio‐ and Z‐Selective Alkyne Hydroamination and Hydrophenoxylation using Tetrafluoro‐λ6‐Sulfanyl Alkynes under Superbasic, Naked Anion Conditions

“…The difference between the activation energy (ΔE ‡ ) and total strain energy corresponds to the interaction energy (E int ), which has a negative value and counteracts the strain energy. [21] We found that the ΔE int term for the processes involving TS-Z and TS-E are nearly identical, but they differ in the ΔE strain (Figure 4b). In this regard, the ΔE strain associated with the pyrazole anion was very low and similar for both pathways; whereas a significant difference was computed for the ΔE strain associated with the Py-SF 4 -alkyne.…”