Ring Contraction of Tropylium Ions into Benzenoid Derivatives.

We report a method to convert substituted tropylium ions into benzenoid derivatives.

Tropylium-Promoted Hydroboration Reactions: Mechanistic Insights Experimental and Computational Studies.

Hydroboration reaction of alkynes is one of the most synthetically powerful tools to access organoboron compounds, versatile precursors for cross-coupling chemistry. This type of reaction has traditionally been mediated by transition-metal or main group catalysts. Herein, we report a novel method using tropylium salts, typically known as organic oxidants and Lewis acids, to promote the hydroboration reaction of alkynes.

Aerobic, metal-free synthesis of 6-chromeno[4,3-]quinolin-6-ones.

A Friedländer-based method for transition-metal free, aerobic synthesis of chromene-fused quinolinones is reported. The coupling of 4-hydrocoumarins and 2-aminobenzyl alcohols proceeds in the presence of acetic acid solvent and oxygen oxidant, affording 6-chromeno[4,3-]quinolin-6-ones in good to excellent yields. The reactions are tolerant of functionalities such as alkyl, methoxy, bromo, chloro, and -heterocycle.