A ring-closing metathesis approach to heterocycle-fused azepines
摘要:
Heterocycle-fused azepines, an important class of molecular scaffold, are readily synthesised through the ruthenium-catalysed ring-closing metathesis reaction. Although benzo-fused azepines are well documented, heterocycle-fused examples are poorly developed. Herein, a range of five- and six-membered heterocycle-fused azepines are investigated, allowing access to a series of pharmaceutically interesting products. (C) 2012 Elsevier Ltd. All rights reserved.
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.
A ring-closing metathesis approach to heterocycle-fused azepines
作者:Thomas A. Moss
DOI:10.1016/j.tetlet.2012.12.042
日期:2013.2
Heterocycle-fused azepines, an important class of molecular scaffold, are readily synthesised through the ruthenium-catalysed ring-closing metathesis reaction. Although benzo-fused azepines are well documented, heterocycle-fused examples are poorly developed. Herein, a range of five- and six-membered heterocycle-fused azepines are investigated, allowing access to a series of pharmaceutically interesting products. (C) 2012 Elsevier Ltd. All rights reserved.