The formation of 1,2-disubstituted adamantanes during the acylation of monosubstituted alkynes with derivatives of 1-adamantanecarboxylic acid

Beyond the Balz–Schiemann Reaction: The Utility of Tetrafluoroborates and Boron Trifluoride as Nucleophilic Fluoride Sources

“…However, for acyl chlorides (as acylium ion precursors) that possess β-hydrogen atoms, the initial electrophilic addition of the acylium ion to the alkyne can be followed by a rapid [1,5]-hydride shift to furnish an alkyl carbocation. This newly formed carbocation can then be intercepted by fluoride transfer from the BF 4 – ion to give alkyl fluoride products. ,,, For example, the reaction of 1-adamantanoyl chloride 367 , AgBF 4 , and various terminal alkynes 368 gave the corresponding 2-fluoroadamantane derivatives 371 in moderate yield (six examples, 40–60% yield) (Scheme ). , Similar results have been reported with cyclohexyl (as opposed to 1-adamantyl) acyl chlorides, giving fluorides in up to 40% yield. , Formally, these reactions are fluorinations of unactivated C­(sp 3 )–H bonds.…”

Directed C–H Functionalization of the Adamantane Framework

“…65 This reactivity mode was utilized in the synthesis of 1-(2-fluoro-1-adamantyl)but-2-en-1-one (113) (Scheme 47). 66 Adamantane-1-carbonyl chloride (111) was treated with one equivalent of silver(I) tetrafluoroborate, which generates an acylium cation/tetrafluoroborate anion pair.…”