Regioselective Fluorohydrin Synthesis from Allylsilanes

06 March 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Allysilanes can be regioselectively transformed into the corresponding 3-silylfluorohydrin in good yield using a sequence of epoxidation followed by treatment with HF-Et3N with or without isolation of the intermediate epoxide. Various silicon-substitution is tolerated, resulting in a range of 2-fluoro-3-silylpropan-1ol products from this method. Whereas other fluorohydrin syntheses by epoxide opening using HF-Et3N generally require more forcing conditions (e.g. higher reaction temperature), opening of allylsilane-derived epoxides with this reagent occurs at room temperature. We attribute this rate acceleration along with the observed regioselectivity to a beta-silyl effect that stabilizes a proposed cationic intermediate. The use of enantioenriched epoxides produces similarly enantioenriched fluorohydrins suggestive of an SN2-type mechanism.



Supplementary materials

Supporting Information
Experimental details for synthesized compounds, spectral information, and copies of NMR spectra.


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