Hydrodeboration of potassium polyfluoroaryl(fluoro)borates with alcohols

• Potassium polyfluoroarylfluoroborates undergo hydrodeboration in aliphatic alcohols.
• Rate of the hydrodeboration reaction depends on the nature of the alcohol.
• Replacement of a primary alcohol to a secondary or tertiary one retards the reaction.
• Fluoride anion scavengers like LiCl accelerate the hydrodeboration.
• Basic additives slow down or completely inhibit the hydrodeboration.

Potassium polyfluoroaryltrifluoroborates, K[ArFBF3] (ArF = C6F5, HC6F4, MeC6F4, 4-MeOC6F4, 4-indol-1-ylC6F4, 4-imidazol-1-ylC6F4, 4-pyrazol-1-ylC6F4, 2,4,6-C6F3H2 and 4-tetrafluoropyridyl), and K[(C6F5)2BF2] undergo hydrodeboration to ArFH in aliphatic alcohols at elevated temperature. At the same conditions, borates K[3,4,5-C6F3H2BF3], K[4-FC6H4BF3] and K[C6H5BF3] remain intact. The presence of base (Et3N, K2CO3 and NaOMe) retards or prevents conversion of K[C6F5BF3]. Attempted hydrodeboration of K[C6F5BF3] in MeCN failed.

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