Chiral ferrocenyl ligands with bidentate pyridine donors. Synthesis and application in Pd-catalyzed asymmetric allylic alkylation of 1,3-diphenylpropenyl-1-esters

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• 作者：Agnieszka Mroczek ; Giulia Erre ; Rossana Taras ; Serafino Gladiali
• 刊名：Tetrahedron: Asymmetry
• 出版年：2010
• 出版时间：4 August 2010
• 年：2010
• 卷：21
• 期：15
• 页码：1921-1927
• 全文大小：597 K

文摘

A synthetic procedure relying on the Friedländer condensation of enantiopure α-amino ferrocenecarboxaldeyde has been devised for the regio-designed elaboration of a pyridine nucleus fused onto the ferrocene scaffold. Three novel bidentate ligands with different pyridine nitrogen donors featuring the [3,2-b]ferrocenopyridine fragment a as the sole chirogenic element have been prepared in enantiopure form through a multi step route involving the diastereoselective deprotonation of a chiral acetal of ferrocenecarboxaldehyde in the stereodetermining step. The ligands were assessed in the Pd-catalyzed allylic alkylation of 1,3-diphenyl-2-propenyl esters with good stereoselectivity.