Fujiwara‐Moritani Assisted Synthesis of Conjugated 2,3‐Dihydrofuran Trienes and Corresponding 2,3‐Dihydrobenzofuran Derivative

• Published in: ChemistrySelect (Weinheim) 2023-01, Vol.8 (2), p.n/a
• Main Authors: Kumar, Sandeep, Chhatwal, Rajni Johar, Maity, Jyotirmoy, Senapati, Nihar Nalini, Prasad, Ashok K.
• Format: Article
• Language: English
• Subjects: 2,3-Dihydrobenzofuran; 2,3-Dihydrofuran; Diacetone-D-glucose; Fujiwara-Moritani reaction; Palladium catalysed C−C bond
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.202204064

Palladium catalysed C−H activation has been carried out on furanoid glycals to afford highly substituted and conjugated 2,3‐dihydrofuran trienes and then its conversion into highly substituted 2,3‐dihydrobenzofuran was achieved starting from commercially available, inexpensive sugar precursor diacetone‐D‐glucose. Claisen‐Schmidt condensation reaction, Fujiwara‐Moritani cross coupling reaction and 6π electro‐cyclisation reaction were utilized as the key steps in this synthetic route. Diacetone‐D‐glucose was converted into dihydrofuran moiety via Claisen Schmidt condensation which was submitted to Fujiwara‐Moritani C−C coupling reaction to afford 2,3‐O‐isopropylidine‐4,5‐disubstituted 2,3‐dihydrofurans. Excellent yields (up to 97 %) were obtained during C−C coupling step which indeed is an accomplishment. Next, two step chemical route was established for conversion of these substituted and conjugated 2,3‐dihydrofuran triene moieties into corresponding substituted 2,3‐dihydrobenzofuran moiety. A highly efficient methodology has been developed for the synthesis of highly substituted and conjugated 2,3‐dihydrofuran trienes and corresponding 2,3‐dihydrobenzofuran derivative starting from diacetone D‐glucose. The synthesis involved Claisen‐Schmidt condensation reaction, Fuziwara‐Moritani cross coupling reaction and 6π electro‐cyclisation reaction for the development of the methodology. Excellent yields were obtained during metal catalysed C−C coupling step which indeed is an accomplishment of the synthetic protocol.