Organoselenchemie in der stereoselektiven Synthese

Abstract

Reaktionen mit Selenreagentien haben in den vergangenen Jahren einen enormen Aufschwung erlebt, und die Chemie mit Selenverbindungen hat sich zu einem überaus nützlichen Werkzeug für Synthesechemiker entwickelt. Die Reaktivitäten selenhaltiger Verbindungen, die sich von denen schwefelhaltiger unterscheiden, haben zu interessanten neuen Synthesemethoden in der Organischen Chemie geführt. Verschiedene funktionelle Gruppen können selektiv und unter sehr milden Bedingungen in komplexe Moleküle eingeführt werden. In diesem Aufsatz werden die Prinzipien der Organoselenchemie im Hinblick auf die stereoselektive Synthese beleuchtet. Durch die einzigartigen Eigenschaften des Selens lassen sich neue und hoch selektive Transformationen entwickeln, die für die Synthese vielseitiger chiraler Synthesebausteine und zur Naturstoffsynthese genutzt werden können.

Structural Stability and Vibrational Analyses of Haloselenonyl Azides, XSeO2-NNN, where X is F, Cl, Br

“…Since selenium compounds are very important in synthesis and also in medical applications [14][15][16][17][18][19][20], we give in the present study the properties of the corresponding selenium compounds (X-SeO2-NNN, X = F, Cl and Br). Especially we were interested in the question, whether or not the selenium atom, being larger than sulfur, could change the geometry such that conjugation between the Se=O and the N=N bonds might be reduced, which would in turn reduce the preference of the gauche conformation over others.…”

Diastereoselective Cyclisation of N‐Alkenylideneamines into 3,4‐Dihydro‐2H‐pyrrol‐1‐ium Halides

“…Inspired by the fact that chiral organoselenenyl halides can stereoselectively react with alkenes on one hand [56,57] and that this methodology has not yet been applied to the inter-or intramolecular additions of imines to alkenes on the other hand, we tried to apply such chiral selenyl bromides to the selenocyclisation of unsaturated imines. The chiral selenyl bromides 22 [58][59][60][61][62][63][64][65][66][67] and 23, [68][69][70][71][72][73][74][75][76][77] generated in situ from the corresponding diselenides and bromine, were applied to the achiral imine 9a at -78°C (Scheme 5).…”

New Developments with Chiral Electrophilic Selenium Reagents

“…Since that time this reaction has been an important tool in the portfolio of organic chemists and is now routinely used even for the synthesis of complex target compounds. Comprehensive reviews on this chemistry have appeared [3][4][5][6][7][8] and in recent times the synthesis of chiral selenium electrophiles and their application in asymmetric synthesis has emerged. This review will highlight new developments using chiral electrophilic selenium compounds as versatile reagents in stereoselective synthesis.…”