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Atom Efficiency (atom + efficiency)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Improving the Atom Efficiency of the Wittig Reaction by a "Waste as Catalyst/Co-catalyst" Strategy,

ANGEWANDTE CHEMIE, Issue 29 2010
Jun-Jie Cao
Perfekte Abfallverwertung: Bei der hier vorgestellten Strategie zu Steigerung der Atomökonomie von Wittig-Reaktionen werden diese zu Tandemreaktionen verknüpft, in denen der nächste Schritt das Beiprodukt Ph3PO direkt als in situ erzeugten Lewis-Base-Katalysator/Cokatalysator nutzt (siehe Schema). [source]

2-Thiazolidinone: A Novel Thiol Protective Surrogate of Complete Atom Efficiency, a Practical Synthesis of (+)-Biotin.

CHEMINFORM, Issue 10 2004
Masahiko Seki
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Fluorous Biphasic Esterification Directed Towards Ultimate Atom Efficiency.

CHEMINFORM, Issue 13 2003
Jiannan Xiang
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Diverse Asymmetric Quinolizidine Synthesis: A Stereodivergent One-Pot Approach

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010
Wei Zhang
Abstract A diverse stereodivergent organocatalytic one-pot addition/cyclization/annulation sequence to optically active quinolizidine derivatives from easily available starting materials is presented. The one-pot sequence relies on a pyrrolidine-catalyzed enantioselective conjugate addition of electron-deficient amide ,-carbons to ,,,-unsaturated aldehydes, spontaneous hemiaminal formation and acid-catalyzed/mediated N -acyliminium ion cyclization to give the quinolizidine framework. Simple tuning of the reaction conditions in the N -acyliminuim ion cyclization step provides a diastereomeric switch, which gives access to both of the two bridgehead epimers through kinetic, thermodynamic or chelation control. The methodology display a broad substrate scope that is demonstrated by the stereoselective formation of indolo-, thieno-, benzofuro-, furo- and different benzoquinolizidine derivatives with high atom efficiency, up to >99% ee and up to >95:5 dr. Due to its efficiency, synthetic diversity and operational simplicity, this protocol has the potential to find important use as a key step in natural product synthesis, biochemistry and pharmaceutical science. The stereochemical outcome of the one-pot sequence was investigated, and the mechanism and origin of stereoselectivity of the different steps is discussed. [source]