Regioselective unusual formation of spirocyclic 4-{2'-benzo(2',3'-dihydro)furo}- 9-methyl-2,3,9-trihydrothiopyrano[2,3-b]indole by 4-exo-trig aryl radical cyclization and rearrangement

K C Majumdar; S Alam

doi:10.1021/ol061531g

Regioselective unusual formation of spirocyclic 4-{2'-benzo(2',3'-dihydro)furo}- 9-methyl-2,3,9-trihydrothiopyrano[2,3-b]indole by 4-exo-trig aryl radical cyclization and rearrangement

Org Lett. 2006 Aug 31;8(18):4059-62. doi: 10.1021/ol061531g.

Authors

K C Majumdar¹, S Alam

Affiliation

¹ Department of Chemistry, University of Kalyani, Kalyani 741235, India. kcm_ku@yahoo.co.in

PMID: 16928073
DOI: 10.1021/ol061531g

Abstract

4-(2'-Bromoaryloxymethylene)-9-methyl-2,3,9-trihydrothiopyrano[2,3-b]indoles under tri-n-butyltin hydride mediated aryl radical cyclization furnished exclusively the 4-{2'-benzo(2',3'-dihydro)furo}-9-methyl-2,3,9-trihydrothiopyrano[2,3-b]indoles in excellent yield (75-80%) via 4-exo-trig cyclization, opening of the oxetene ring, and 5-endo-trig cyclization.