An Expeditious Route to <i>trans</i>‐Configured Tetrahydrothiophenes Enabled by Fe(OTf)₃‐Catalyzed [3+2] Cycloaddition of Donor–Acceptor Cyclopropanes with Thionoesters

Abstract

Abstract A synthetic route to trans ‐configured tetrahydrothiophenes (THTs) through Fe(OTf) 3 ‐promoted [3+2] cycloaddition of donor–acceptor cyclopropanes with thionoesters was developed. The cycloaddition proceeded in high yield with high diastereoselectivity, affording transient α‐alkoxy THTs. Not only aromatic and aliphatic thionoesters, but also thionolactone were applicable to the present iron catalysis. Further transformation of the S,O‐ketal functionality of the product was achieved in a highly trans diastereoselective manner. Moreover, the utility of our methodology was clearly demonstrated by the synthesis of enantioenriched trans ‐configured THTs.