1313239-36-9Relevant academic research and scientific papers
Platinum catalyzed 7-endo cyclization of internal alkynyl amides and its application to synthesis of the caprazamycin core
Tsukano, Chihiro,Yokouchi, Shinsuke,Girard, Anne-Lise,Kuribayashi, Toshifumi,Sakamoto, Shota,Enomoto, Taro,Takemoto, Yoshiji
, p. 6074 - 6086 (2012/09/05)
The scope and limitations of the platinum catalyzed 7-endo cyclization of internal alkynyl amides were investigated. Substitution of the alkyne with an aryl group gave better results, presumably because it stabilized the transition state. Applying the reaction to a secondary amide, the caprazamycin core was successfully synthesized from commercially available material in eight steps.
Control of 6-Exo and 7-Endo cyclizations of alkynylamides using platinum and bismuth catalysts
Girard, Anne-Lise,Enomoto, Taro,Yokouchi, Shinsuke,Tsukano, Chihiro,Takemoto, Yoshiji
, p. 1321 - 1324 (2013/01/11)
The rules of cyclization: Alkynylamides are regioselectively cycloisomerized into piperazin-2-one and 1,4-diazepan-2-one derivatives by using catalytic amounts of appropriate metal catalysts. A 6-exo-dig addition proceeds in the presence of Bi(OTf)3, while the 7-endo-dig addition occurs with PtCl2 for the same substrate. (see scheme; Ns=o- nitrobenzenesulfonyl, Ts=p-toluenesulfonyl, Cbz=benzyloxycarbonyl, DCE=dichloroethane) Copyright
