1226974-91-9Relevant academic research and scientific papers
Diastereoselective syntheses of indoloquinolizidines by a pictet-spengler/lactamization cascade
Fang, Huihui,Wu, Xiaoyu,Nie, Linlin,Dai, Xiaoyang,Chen, Jie,Cao, Weiguo,Zhao, Gang
, p. 5366 - 5369 (2011/03/19)
An expedient diastereoselective synthesis of highly functionalized indolo[2,3-α]quinolizidines adopting a cis H2/H12b geometry has been realized by a Pictet-Spengler/lactamization cascade sequence. The absolute stereochemistry at C2, C3, and C12b was gove
Diverse asymmetric quinolizidine synthesis: A stereodivergent one-pot approach
Zhanga, Wei,Franzena, Johan
supporting information; experimental part, p. 499 - 518 (2010/06/17)
A diverse stereodivergent organocatalytic one-pot addition/cyclization/ annulation sequence to optically active quinolizidine derivatives from easily available starting materials is presented. The one-pot sequence relies on a pyrrolidine-catalyzed enantioselective conjugate addition of electron-deficient amide a-carbons to α,β-unsaturated aldehydes, spontaneous hemiaminal formation and acid-catalyzed/mediated N-acyliminium ion cyclization to give the quinolizidine framework. Simple tuning of the reaction conditions in the N-acyliminuim ion cyclization step provides a diastereomeric switch, which gives access to both of the two bridgehead epimers through kinetic, thermodynamic or chelation control. The methodology display a broad substrate scope that is demonstrated by the stereoselective formation of indolo-, thieno-, benzofuro-, furo- and different benzoquinolizidine derivatives with high atom efficiency, up to >99% ee and up to >95:5 dr. Due to its efficiency, synthetic diversity and operational simplicity, this protocol has the potential to find important use as a key step in natural product synthesis, biochemistry and pharmaceutical science. The stereochemical outcome of the one-pot sequence was investigated, and the mechanism and origin of stereoselectivity of the different steps is discussed.
