Regio- and Stereoselective Oxysulfonylation of Allenes

A highly regio- and stereoselective oxysulfonylation of allenes was developed that provided direct access to 2-sulfonyl allylic alcohols in good yields. By means of dioxygen activation, selective difunctionlization of allenes could be successfully achieved under mild metal-free conditions. Preliminary mechanistic investigation disclosed that this transformation probably goes through a radical process

Dioxygen-Triggered Oxidative Radical Reaction: Direct Aerobic Difunctionalization of Terminal Alkynes toward β‑Keto Sulfones

An unprecedented dioxygen-triggered oxidative radical process was explored using dioxygen as the solely terminal oxidant, realizing aerobic oxidaitve difunctionalization of terminal alkynes toward β-keto sulfones with high selectivity. Operando IR experiments revealed that pyridine not only acts as a base to successfully surpress ATRA (atom transfer radical addition) process, but also plays a vital role in reducing the activity of sulfinic acids

NMP and O₂ as Radical Initiator: Trifluoromethylation of Alkenes to Tertiary β‑Trifluoromethyl Alcohols at Room Temperature

A novel strategy was developed to trigger ·CF₃ by using <i>in situ</i> generated peroxide in NMP under O₂ or air as the radical initiator. Radical trifluoromethylation of alkenes was achieved toward tertiary β-trifluoromethyl alcohols. Various tertiary β-trifluoromethyl alcohols can be synthesized in good yields without extra oxidants or transition metal catalysts. Preliminary mechanistic investigation revealed that O₂ diffusion can influence the reaction rate

Copper-/Cobalt-Catalyzed Highly Selective Radical Dioxygenation of Alkenes

A highly selective radical dioxygenation of alkenes using hydroxamic acid and O₂ was developed, and copper/cobalt was used as the catalyst without assistance of any additional ligands or bases. Mechanistic investigation disclosed that copper salt and O₂ work in concert to activate hydroxamic acid, with Cu­(I) and Cu­(II) concurrently existing in this reaction