title: 3-Alkenylation or 3-alkylation of indole with propargylic alcohols: construction of 3,4-dihydrocyclopenta[b]indole and 1,4-dihydrocyclopenta[b]indole in the presence of different catalysts.
abstract: 3-Alkenylation or 3-alkylation of indole with propargylic alcohols could be efficiently controlled by the catalyst. In the presence of triflic acid, 3-alkenylation of indole occurred and a 3,4-dihydrocyclopenta[b]indole skeleton was effectively constructed in moderate to excellent yields via a cascade process. In the presence of Cu(OTf)(2), 3-alkylation of indole resulted in the formation of 3-propargylic indole, which could be further converted into 2-iodo-1,4-dihydrocyclopenta[b]indoles in the presence of N-iodosuccinimide and boron trifluoride etherate. Possible mechanisms related to the 3-alkenylation or 3-alkylation of indole and their extension to the formation of 3,4-dihydrocyclopenta[b]indoles or 1,4-dihydrocyclopenta[b]indoles are postulated and discussed.
authors.affiliation: Department of Chemistry, Zhejiang University, Hangzhou 310027, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Yuanxun
authors.initials: Y
authors.lastname: Zhu
authors.forename: Guangwei
authors.initials: G
authors.lastname: Yin
authors.forename: Ping
authors.initials: P
authors.lastname: Lu
authors.forename: Yanguang
authors.initials: Y
authors.lastname: Wang