Studies on the reactivity of N-(3-thienyl)carbamates

Abstract

tert-Butyl 2-allyl- and N-allyl-3-thienylcarbamates were used as substrates for the preparation of thieno[3,2-b]pyrroles 9 and 5,6-dihydrothieno[3,2-b]pyrroles 10. Pd-catalyzed cyclization of N-allyl-(2-bromo-3-thienyl)carbamates 12 has allowed access to thienopyrroles 9. The radical route has led to the formation of a dihydrothienopyrrole 10 or a tetrahydrothienopyridine 19 according to the β-substitution of the allyl substituent. The nucleophilic participation of the tert-butoxycarbonyl group occurred during the selenium or iodine-induced cyclization of tert-butyl 2-allyl- or N-allyl-3-thienylcarbamates. The formation of the thienooxazepinone 25 and N-(3-thienyl)oxazolidinones 28 and 29 was observed.