Generation of Quaternary Carbons in Cycloalkanones and Lactones with Arynes through a Domino Process.

A synthetic method was developed for the generation of a quaternary carbon center in carbonyl compounds. This innovative process involved the reaction of α-thiolate lactones and cycloalkanones with two equivalents of arynes in acetonitrile to give α,α-diarylated products in 63-85% yields at 25 °C. The reaction unfolds through an unconventional domino process, encompassing sequential 1,2-elimination, 1,2-nucleophilic addition, 1,4-proton transfer, the second 1,2-nucleophilic addition, interrupted Pummerer rearrangement, intramolecular spirocyclization, and sulfonium ring-opening. The potential of this "single-flask" reaction was systematically investigated and found well-suited to generate diarylated carbonyl compounds, incorporating naphthalene, pyridine, quinoline, or isoquinoline rings adorned with various substituents.