Structural optimization of thiourea-based bifunctional organocatalysts for the highly enantioselective dynamic kinetic resolution of azlactones
作者:Albrecht Berkessel、Santanu Mukherjee、Thomas N. Müller、Felix Cleemann、Katrin Roland、Marc Brandenburg、Jörg-M. Neudörfl、Johann Lex
DOI:10.1039/b607574f
日期:——
describes the synthesis of a library of structurally diverse bifunctionalorganocatalysts bearing both a quasi-Lewis acidic (thio)urea moiety and a Bronsted basic tertiary amine group. Sequential modification of the modular catalyst structure and subsequent screening of the compounds in the alcoholytic dynamickineticresolution (DKR) of azlactones revealed valuable structure-activity relationships. In particular
Quinine-Derived Imidazolidin-2-imine Ligands: Synthesis, Coordination Chemistry, and Application in Catalytic Transfer Hydrogenation
作者:Sabina-Alexandra Filimon、Cristian G. Hrib、Sören Randoll、Ion Neda、Peter G. Jones、Matthias Tamm
DOI:10.1002/zaac.200900485
日期:2010.4
Two new optically active bidentate N,N-ligands, DMIQCI (3a) and DMIQCD (3b), containing a quinuclidine core and an imidazolidin-2-imine unit, were synthesized. The reaction of these ligands with [(η5-C5Me5)RuCl]4 afforded the brick-red ruthenium(II) complexes [(η5-C5Me5)Ru(DMIQCI)Cl] (4) and [(η5-C5Me5)Ru(DMIQCD)Cl] (5), which were used as catalysts in the transfer hydrogenation of acetophenone in
SN2 reactions at carbon C9 of Quincorine (QCI) and Quincoridine (QCD) were investigated and found to be difficult, due to the special structural (‘β-amino effect’) and conformational factors. Efficient experimental procedures for displacement with a variety of carbon and heteroatom nucleophiles were developed.
由于特殊的结构(“β-氨基效应”)和构象因素,研究了在奎宁碱(QCI)和奎宁丁(QCD)的碳C9处的S N 2反应是困难的。开发了用于替换各种碳原子和杂原子亲核试剂的高效实验程序。
Truncated Cinchona alkaloids as catalysts in enantioselective monobenzoylation of meso-1,2-diols
作者:E. Peter Kündig、Alvaro Enriquez Garcia、Thierry Lomberget、Pablo Perez Garcia、Patrick Romanens
DOI:10.1039/b808268e
日期:——
Readily synthesised quincorine and quincoridine derived chiral diamines efficiently catalyse the asymmetric monobenzoylation of cyclic and acyclic meso-1,2-diols.
New Members of the Cinchona Alkaloid Family: 9-Aminoquincorine-10-aldehyde and 9-Aminoquincoridine-10-aldehyde
作者:Ion Neda、Elena Fodor、Catalin V. Maftei、Monica Mihorianu、Horst-Dieter Ambrosi、M. Heiko Franz
DOI:10.1002/ejoc.201301286
日期:2013.12
This paper reports the synthesis of the new enantiopure amino aldehydes, 9-aminoquincorine-10-aldehyde (1) and 9-aminoquincoridine-10-aldehyde (2). These alkaloid-like compounds are derivatives of the Cinchonaalkaloidsquinine and quinidine. Their application as chiral building blocks in the synthesis of novel compounds is demonstrated by the reduction and reductive amidation of the aldehyde moiety