Ene reactions of 2-borylated α-methylstyrenes: a practical route to 4-methylenechromanes and derivatives. Issue 23 (28th May 2019)

• Record Type: Journal Article
• Authors: Boureghda, Chaima; Macé, Aurélie; Berrée, Fabienne; Roisnel, Thierry; Debache, Abdelmadjid; Carboni, Bertrand
• Is Part Of: Organic & biomolecular chemistry. Volume 17:Issue 23(2019)
• Page Start: 5789
• Page End: 5800
• Publication Date: 2019-05-28
• Subjects: Chemistry, Organic -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1039/c9ob00963a
• Languages: English
• ISSNs: 1477-0520

Abstract

Abstract : 4-Methylenechromanes were prepared via a three-step process from 2-borylated α-methylstyrenes using a glyoxylate-ene reaction catalyzed by scandium(iii ) triflate and Mitsunobu cyclization as key steps. Abstract : 4-Methylenechromanes were prepared via a three-step process from 2-borylated α-methylstyrenes. This sequence is based on a key glyoxylate-ene reaction catalyzed by scandium(iii ) triflate. The resulting γ-hydroxy boronates, which cyclise to seven-membered homologues of benzoxaborole on silica gel, were cleanly oxidized with sodium perborate, and then cyclised under Mitsunobu conditions. Additionally, several further functional transformations of 4-methylenechromanes or their precursors were carried out to illustrate the synthetic potential of these intermediates.