Acid-promoted cyclization of 2,4-diaryl-1,1,1-trifluorobut-3-en-2-oles and their TMS-ethers into CF3-indenes

Matvei Yu Martynov; Roman O Iakovenko; Anna N Kazakova; Irina A Boyarskaya; Aleksander V Vasilyev

doi:10.1039/c7ob00406k

Acid-promoted cyclization of 2,4-diaryl-1,1,1-trifluorobut-3-en-2-oles and their TMS-ethers into CF₃-indenes

Org Biomol Chem. 2017 Mar 22;15(12):2541-2550. doi: 10.1039/c7ob00406k.

Authors

Matvei Yu Martynov¹, Roman O Iakovenko¹, Anna N Kazakova¹, Irina A Boyarskaya¹, Aleksander V Vasilyev²

Affiliations

¹ Institute of Chemistry, Saint Petersburg State University, Universitetskaya nab., 7/9, Saint Petersburg, 199034, Russia.
² Institute of Chemistry, Saint Petersburg State University, Universitetskaya nab., 7/9, Saint Petersburg, 199034, Russia and Department of Chemistry, Saint Petersburg State Forest Technical University, Institutsky per., 5, Saint Petersburg, 194021, Russia. aleksvasil@mail.ru.

PMID: 28261737
DOI: 10.1039/c7ob00406k

Abstract

2,4-Diaryl-1,1,1-trifluorobut-3-en-2-oles and their TMS-ethers in H₂SO₄ at room temperature in just 2 min are quantitatively cyclized into 1-aryl-3-trifluoromethyl-1H-indenes. The reaction proceeds through an intermediate formation of the corresponding CF₃-allyl cations, which are cyclized regioselectively at the allyl carbon atom most remote from the CF₃-group. The obtained CF₃-indenes in solution of EtOAc in the presence of silica gel at room temperature over 4 h are quantitatively isomerized into 3-aryl-1-trifluoromethyl-1H-indenes.