Practical highly enantioselective synthesis of terminal propargylamines. An expeditious synthesis of (S)-(+)-coniine
作者:Nina Gommermann、Paul Knochel
DOI:10.1039/b409951f
日期:——
The one-pot three-component addition reaction of trimethylsilylacetylene, aldehydes and dibenzylamine provides in the presence of CuBr/Quinap as catalyst, various enantiomerically enriched propargylamines in good yields (up to 99%) and excellent enantiomeric excess (up to 98%
ee) which can be used as a key intermediate in the synthesis of the alkaloid (S)-(+)-coniine.
N,N-DIBENZYL-N-[1-CYCLOHEXYL-3-(TRIMETHYLSILYL)-2-PROPYNYL]-AMINE FROM CYCLOHEXANECARBALDEHYDE, TRIMETHYLSILYLACETYLENE AND DIBENZYLAMINE
作者:Gommermann, Nina、Knochel, Paul、Rech, Jason C.、Ellman, Jonathan A.
DOI:10.15227/orgsyn.084.0001
日期:——
Diastereofacial π-Stacking as an Approach To Access an Axially Chiral P,N-Ligand for Asymmetric Catalysis
作者:Balaji V. Rokade、Patrick J. Guiry
DOI:10.1021/acscatal.6b03427
日期:2017.4.7
A phosphino-imidazoline (PHIM) ligand possessing axial chirality is prepared in a straightforward five-step synthesis. Configurational stability around the chiral axis is achieved by the diastereofacial pi-stacking between the pentafluorophenyl and the naphthalene rings. In particular, access to enantiopure ligand (S,S,R-a)-2a was realized by fractional crystallization of the corresponding similar to 3:1 atropdiastereomeric mixture. The preliminary application of ligand (S,S,R-a)-UCD-PHIM showed excellent activities in the enantioselective copper-catalyzed A3 coupling (ee's up to 98.1% and yields up to 98%).