Liu Cong, Widenhoefer Ross A
P. M. Gross Chemical Laboratory, Duke University, Durham, NC 27708-0346, USA.
J Am Chem Soc. 2004 Aug 25;126(33):10250-1. doi: 10.1021/ja046810i.
Reaction of 1-methyl-2-(4-pentenyl)indole with a catalytic amount of PdCl2(CH3CN)2 (5 mol %) and a stoichiometric amount of CuCl2 (3 equiv) in methanol under CO (1 atm) at room temperature for 30 min led to cyclization/carboalkoxylation to form the corresponding tetrahydrocarbazole in 83% isolated yield as a single regioisomer. Palladium-catalyzed cyclization/carboalkoxylation of 2-(4-pentenyl)indoles tolerated substitution along the alkenyl chain and at the internal and cis-terminal olefinic positions. Palladium-catalyzed cyclization/carboalkoxylation tolerated a range of alcohols and was effective for the cyclization of 2-(3-butenyl)indoles, 3-(3-butenyl)indoles, 3-(4-pentenyl)indoles, and 2-(5-hexenyl)indoles.
1-甲基-2-(4-戊烯基)吲哚在室温下于甲醇中，在1个大气压的CO氛围下，与催化量的PdCl2(CH3CN)2（5 mol%）和化学计量的CuCl2（3当量）反应30分钟，发生环化/碳烷氧基化反应，以83%的分离产率形成相应的四氢咔唑，且为单一区域异构体。2-(4-戊烯基)吲哚的钯催化环化/碳烷氧基化反应能够耐受沿烯基链以及在内部和顺式末端烯烃位置的取代。钯催化的环化/碳烷氧基化反应能耐受多种醇类，并且对2-(3-丁烯基)吲哚、3-(3-丁烯基)吲哚、3-(4-戊烯基)吲哚和2-(5-己烯基)吲哚的环化反应有效。
