Cyclization of 1-bromo-2,7- and 1-bromo-2,8-enynes mediated by indium

ORGN 114

Phil Ho Lee, phlee@kangwon.ac.kr, Sundae Kim, and Hyunseok Kim. Department of Chemistry, Kangwon National University, Hyoga-2-dong 192-1, Chunchon, 200-701, South Korea
The cyclization of 1-bromo-2,7- and 1-bromo-2,8-enynes mediated by indium in DMF produced five- and six-membered cyclic compounds. Although KI was a necessary additive in the cyclization of terminal 1-bromo-2,7-enynes to give the desired products at 25oC, reactions of terminal 1-bromo-2,8-enynes and internal 1-bromo-2,7-enynes with indium proceeded at 100oC in DMF without KI. After cyclizations, subsequent cross-coupling reaction and iodolysis increase the usefulness of this reaction.