Cyclopropenimine-Catalyzed Enantioselective Mannich Reactions of <i>tert</i>-Butyl Glycinates with <i>N</i>-Boc-Imines
作者:Jeffrey S. Bandar、Tristan H. Lambert
DOI:10.1021/ja407277a
日期:2013.8.14
shown to catalyze Mannichreactions between glycine imines and N-Boc-aldimines with high levels of enantio- and diastereocontrol. The reactivity of 1 is shown to be substantially greater than that of a widely used thiourea cinchona alkaloid-derived catalyst. A variety of aryl and aliphatic N-Boc-aldimines are effective substrates for this transformation. A preparative-scale reaction to deliver >90 mmol
Synthesis of novel multi-functionalized pyrrolidines by [3 + 2] dipolar cycloaddition of azomethine ylides and vinyl ketones
作者:Marko S. Pešić、Jovana P. Bugarinović、Aleksandra Minić、Danijela Ilić Komatina、Anka Pejović、Biljana Šmit、Dragana Stevanović、Ivan Damljanović
DOI:10.1007/s00706-018-2340-6
日期:2019.4
AbstractAn efficient and easy synthetic route to substituted pyrrolidine derivatives has been established through [3 + 2] dipolar cycloaddition of vinyl ketones and azomethine ylides. The reactions proceed smoothly, under mild conditions, affording moderate to high isolated yields (up to 88%) of the products, within a short reaction time (15–45 min), providing a series of novel potentially bioactive
Cyclopalladation of Schiff Bases from Methyl Esters of α-Amino Acids. Unexpected Activation of the O−Me Bond with Formation of a Bianionic Tridentate Metallacycle
methyl esters of the α-amino acids glycine, alanine, valine, and tyrosine is herein described. The reactivity of the new metallacycles obtained with phosphines and amines is also described, as well as the synthesis of isoquinolinium salts by insertion of diphenylacetylene into the Pd−C bond. Besides this, the unexpected activation of the Me−O bond of the ester group of the amino acid fragment is also reported
The influence of imine structure, catalyst structure and reaction conditions on the enantioselectivity of the alkylation of alanine methyl ester imines catalyzed by Cu(ch-salen)
作者:Yuri N Belokon’、R.Gareth Davies、Jose A Fuentes、Michael North、Teresa Parsons
DOI:10.1016/s0040-4039(01)01718-x
日期:2001.11
Systematic variation of the substrate structure has shown that the most effective substrates for Cu(ch-salen)-catalyzed asymmetric enolate alkylation reactions carried out under phase-transfer conditions are the para-chlorophenyl imines of amino esters. The other reaction parameters (solvent and stirring speed) have also been optimized. The introduction of substituents onto the aryl rings of the salen ligand was found not to have a beneficial effect on the enantioselectivity of the reaction. (C) 2001 Elsevier Science Ltd. All rights reserved.