کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1326082 | 1499953 | 2005 | 24 صفحه PDF | دانلود رایگان |
The preparation of a variety of chiral N-heterocyclic carbene (NHC) precursors is described. The relative merits of imidazolinium salts and silver carbenes as NHC precursors are discussed with respect to their synthesis, stability and performance in the copper catalysed conjugate addition of dialkyl zinc reagents to a variety of Michael acceptors. Enantioselectivities of up to 93% were achieved using as little as 4% of chiral ligand.
Chiral N-heterocyclic carbenes have been shown to be excellent ligands for the copper catalysed conjugate addition of dialkyl zinc reagents to various Michael acceptors. Up to 93% enantiomeric excess has been achieved for the addition of diethyl zinc to cycloheptenone using as little as 4 mol% of catalyst.Figure optionsDownload as PowerPoint slide
Journal: Journal of Organometallic Chemistry - Volume 690, Issues 24–25, 1 December 2005, Pages 5672–5695