Access to benzo-fused nine-membered heterocyclic alkenes with a trifluoromethyl carbinol moiety via a double decarboxylative formal ring-expansion process under palladium catalysisElectronic supplementary information (ESI) available: CCDC 1575063, 1575065, 1575062, 1589030. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc05447e

• Main Authors: Das, Pulakesh, Gondo, Satoshi, Nagender, Punna, Uno, Hiroto, Tokunaga, Etsuko, Shibata, Norio
• Format: Article
• Language: English
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c7sc05447e

Direct access to pharmaceutically attractive benzo-fused nine-membered heterocyclic alkenes 3 with a trifluoromethyl carbinol moiety was achieved via a palladium-catalyzed double-decarboxylative formal ring-expansion process from six-membered trifluoromethyl benzo[ d ][1,3]oxazinones 1 to nine-membered trifluoromethyl benzo[ c ][1,5]oxazonines 3 in the presence of vinylethylene carbonates 2 . Generation of a Pd-π-allyl zwitterionic intermediate was proposed in the catalytic cycle. The trifluoromethyl group in the benzoxazinanones 1 plays an important role throughout the transformation. Diastereoselective chemical transformations of products 3 were also demonstrated. Direct access to benzo-fused nine-membered heterocyclic alkenes with a trifluoromethyl carbinol moiety was achieved via a palladium-catalysis.