Transition-metal-free intramolecular Friedel-Crafts reaction by alkene activation: A method for the synthesis of some novel xanthene derivatives


YILDIZ T., Bastas I., BAŞPINAR KÜÇÜK H.

BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY, vol.17, pp.2203-2208, 2021 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 17
  • Publication Date: 2021
  • Doi Number: 10.3762/bjoc.17.142
  • Journal Name: BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aquatic Science & Fisheries Abstracts (ASFA), Biotechnology Research Abstracts, Chemical Abstracts Core, Directory of Open Access Journals
  • Page Numbers: pp.2203-2208
  • Keywords: alkene activation, intramolecular Friedel-Crafts alkylation, trifluoroacetic acid, xanthene, ONE-POT SYNTHESIS, ORTHO-QUINONE METHIDES, EFFICIENT SYNTHESIS, UNACTIVATED ALKENES, HYDROARYLATION, CYCLIZATION, XANTHONES, ARYNES, THIOXANTHONES, BUTOXIDE
  • Istanbul University Affiliated: No

Abstract

In this work, new derivatives (substituted 9-methyl-9-arylxanthenes) of xanthene compounds (5a-l) of possible biological significance were synthesized by developing a new synthesis method. In order to obtain xanthene derivatives, the original alkene compounds to be used as the starting materials were synthesized in four steps using appropriate reactions. A cyclization reaction by intramolecular Friedel-Crafts alkylation was carried out in order to synthesize the desired xanthene derivatives using the alkenes as starting compounds. The intramolecular Friedel-Crafts reaction was catalyzed by trifluoroacetic acid (TFA) and provided some novel substituted 9-methyl-9-arylxanthenes with good yields at room temperature within 6-24 hours. As a result, an alkene compound was used for activation with TFA in the synthesis of xanthene through intramolecular Friedel-Crafts alkylation for the first time.