Cyclization of 1-bromo-2,7- and 1-bromo-2,8-enynes mediated by indium
Phil Ho Lee1, Sundae Kim, Kooyeon Lee
1Department of Chemistry, Kangwon National University, Chunchon 200-701, Republic of Korea. phlee@kangwon.ac.kr
Abstract:
[reaction: see text] 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 25 degrees C, reactions of terminal 1-bromo-2,8-enynes and internal 1-bromo-2,7-enynes with indium proceeded at 100 degrees C in DMF without KI. After cyclizations, subsequent cross-coupling reaction and iodolysis increase the usefulness of this reaction.
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