Stereoselective Synthesis of Benzoxepines through Tandem Alkylation/Michael Addition to Vinylogous Carbonates

Substituent-Controlled Copper-Catalyzed Trifluoromethylation of 1,7-Dienes: Synthesis of Mono- and Bis-trifluoromethylated Benzoxepines

A copper-catalyzed trifluoromethylation of benzene-linked 1,7-dienes with 1-trifluoromethyl-1,2-benziodoxole via a radical cascade cyclization process for the synthesis of mono- and bis-trifluoromethylated benzoxepines is developed. The selectivity depends on substituents on the double bond of the allyl group in 1,7-dienes. The large-scale operation and late-stage functionalization of bioactive molecules reveal the promising utility of this protocol.

Visible-light-induced radical cascade cyclization of 1-(allyloxy)-2-(1-arylvinyl)benzenes with sulfonyl chlorides for the synthesis of sulfonated benzoxepines

A visible light photocatalyzed cascade sulfonylation/cyclization of 1-(allyloxy)-2-(1-arylvinyl)benzenes with sulfonyl chlorides for the construction of sulfonated benzoxepines is developed.

Base-Free and Catalyst-Free Synthesis of Functionalized Dihydrobenzoxazoles via Vinylogous Carbonate to Carbamate Rearrangement

An unexpected, catalyst-free, and base-free intramolecular cyclization of N-aryloxyacrylate aldimines, under thermal conditions leading to the synthesis of functionalized dihydrobenzoxazoles, is reported. The reaction features a unique rearrangement of vinylogous carbonates to vinylogous carbamates resulting in a new carbon-oxygen and carbon-nitrogen bond construction. The reaction tolerates a broad range of functional groups and the desired products are formed in moderate to good yields.

Base-Promoted Formal [4 + 3] Annulation between 2-Fluorophenylacetylenes and Ketones: A Route to Benzoxepines

The first base-promoted formal [4 + 3] annulation between 2-fluorophenylacetylenes and ketones has been disclosed. The reaction proceeds through a tandem α-vinylation of ketones followed by an intramolecular nucleophilic aromatic substitution (SNAr) reaction of the in situ generated β,γ-unsaturated ketone intermediates, providing a straightforward access to a wide range of functionalized benzoxepines in moderate to high yields. The transition-metal-free methodology featured a wide substrate scope, the use of easily available starting materials, and a high functional group tolerance.