Proline‐Mediated Enantioselective Construction of Tetrahydropyridines<i>via</i>a Cascade Mannich‐Type/Intramolecular Cyclization Reaction
作者:Rong‐Gang Han、Yao Wang、Yu‐Ye Li、Peng‐Fei Xu
DOI:10.1002/adsc.200800253
日期:2008.7.7
A highly diastereo- and enantioselective synthesis of 2,3-disubstituted tetrahydropyridines was accomplished via a proline-mediated cascade Mannich-type/intramolecularcyclizationreaction from preformed N-PMP (p-methoxyphenyl) aldimines and inexpensive aqueous tetrahydro-2H-pyran-2,6-diol.
A Modified and Highly Useful Protocol for the Brønsted Acid Catalyzed, Enantioselective, Vinylogous Mannich Reaction with Aliphatic Aldimines
作者:Christoph Schneider、Falko Abels
DOI:10.1055/s-0031-1289303
日期:2011.12
Highly enantioselective as well as diastereoselective catalytic vinylogousMannichreactions have been accomplished for the first time with aliphatic straight-chain aldimines and O,O-silylketene acetals and furnish valuable synthetic building blocks in high enantiomeric purity. vinylogousMannichreaction - phosphoric acid - organocatalyis - contact ion pair - dienolate - BINOL
A simple and efficient method for the synthesis of 1,3,4-trisubstituted or 3,4-disubstituted pyrroles has been developed. The reaction represents the first time that pyrroles are synthesized directly from readily available aldehydes and amines (anilines) as starting materials. This method has been successfully applied to the rapid synthesis of purpurone.
Synthesis of β-lactams by condensation of titanium enolates of 2-pyridylthioesters with imines. Influence of the imine structure on the trans/cis stereoselectivity
The condensation of the titanium enolates of C-2 alkyl substituted 2-pyridylthioesters with imines affords beta-lactams in trans/cis ratios that largely depend on the structure of the C-imine residue. Bulky and non-chelating heteroatom-containing groups lead to the formation of trans p-lactams, while sterically non-requiring or chelating groups favour the formation of the cia-products. On the basis of NMR evidences a rationale is proposed to account for the observed stereoselectivity.
Li, Jianhui; Wang, Zhouyu; Jiang, Zhenju, Asian Journal of Chemistry, 2011, vol. 23, # 9, p. 4101 - 4103