A Configurational Switch Based on Iridium-Catalyzed Allylic Cyclization: Application in Asymmetric Total Syntheses of Prosopis, Dendrobate, and Spruce Alkaloids
作者:Christian Gnamm、Kerstin Brödner、Caroline M. Krauter、Günter Helmchen
DOI:10.1002/chem.200901316
日期:2009.10.12
A method for the stereoselectivesynthesis of 2,6‐disubstituted piperidines has been developed that is based on the use of an intramolecular iridium‐catalyzed allylic substitution as a configurational switch. The procedure allows the preparation of 2‐vinylpiperidines with enantiomeric excesses (ee) of greater than 99 %. As applications, total syntheses of piperidine alkaloids have been elaborated,
Stereoselective Synthesis of 2,6-Disubstituted Piperidines Using the Iridium-Catalyzed Allylic Cyclization as Configurational Switch: Asymmetric Total Synthesis of (+)-241 D and Related Piperidine Alkaloids
作者:Christian Gnamm、Caroline M. Krauter、Kerstin Brödner、Günter Helmchen
DOI:10.1002/chem.200802525
日期:2009.2.16
configurational switch: Use of enantiomeric Ir catalysts allows the vinylpiperidine building blocks 2 a and 2 b to be synthesized with high selectivity. Total syntheses of the dendrobate alkaloid (+)‐241 D, its C6‐epimer, and a spruce alkaloid are presented as applications.
Access to 2,6-Disubstituted 4-Oxopiperidines Using a 6-<i>Endo</i>-<i>trig</i> Cyclization: Stereoselective Synthesis of Spruce Alkaloid and (+)-241D
作者:Alexander H. Harkiss、Andrew Sutherland
DOI:10.1021/acs.joc.7b02799
日期:2018.1.5
providing the corresponding 4-oxopiperidines in high yields (80–89%). Stereoselective reduction of the 2,6-cis-disubstituted 4-oxopiperidines then gave the 2,4,6-cis,cis-trisubstituted 4-hydroxypiperidines in high diastereoselectivity. The general nature of this approach was demonstrated with the synthesis of the natural products, spruce alkaloid and (+)-241D.