ChemInform Abstract: ACYLATION OF CYCLOBUTANE OLEFINS

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

“…A similar acylfluorination of 1-methylcyclobutene 356 with [MeCO + ]­[BF 4 – ] afforded a 68:32 mixture of diastereoisomeric β-fluoro ketone products 357 and 358 , respectively, in 76% combined yield, consistent with the intermediacy of a cyclobutyl carbocation (Scheme ) . Similar fluorine incorporation has been observed in the reaction of 1,3,3-trimethylcyclopropene with [MeCO + ]­[BF 4 – ], although fluoride trapping was preceded in this case by electrocyclic opening of the cyclopropyl cation, resulting in an allylic fluoride product…”