Gold-Catalyzed [4C+2C] Cycloadditions of Allenedienes, including an Enantioselective Version with New Phosphoramidite-Based Catalysts: Mechanistic Aspects of the Divergence between [4C+3C] and [4C+2C] Pathways
作者:Isaac Alonso、Beatriz Trillo、Fernando López、Sergi Montserrat、Gregori Ujaque、Luis Castedo、Agustí Lledós、Jose L. Mascareñas
DOI:10.1021/ja905415r
日期:2009.9.16
Gold(I) complexes featuring electron acceptor ligands such as phosphites and phosphoramidites catalyze the [4C+2C] intramolecular cycloaddition of allenedienes. The reaction is chemo- and stereoselective, and provides trans-fused bicyclic cycloadducts in good yields. Moreover, using novel chiral phosphoramidite-based gold catalysts it is possible to perform the reaction with excellent enantioselectivity
isopropylidene acetal unit from well‐known TADDOLligands improved the performance of the derived phosphoramiditeligands in asymmetric goldcatalysis (see scheme; Ts=4‐toluenesulfonyl). X‐ray crystallography showed that the binding pocket has an effective threefold symmetry, with through‐space interactions between the arene rings of the ligand and the gold center.
Mauleon, Pablo; Zeldin, Rachel M.; Gonzalez, Ana Z., Journal of the American Chemical Society, 2009, vol. 131, p. 6348 - 6349
作者:Mauleon, Pablo、Zeldin, Rachel M.、Gonzalez, Ana Z.、Toste, F. Dean
DOI:——
日期:——
Gold(I)-Catalyzed Enantioselective [4 + 2]-Cycloaddition of Allene-dienes
作者:Ana Z. González、F. Dean Toste
DOI:10.1021/ol902622b
日期:2010.1.1
An enantioselective gold(I)-catalyzed intramolecular [4 + 2]-cycloaddition of allenes and dienes is reported. The reactions allow for the asymmetric synthesis of trans-hexahydroindenes and pyrrolidine products using C3-symmetric phosphitegold(I) and ortho-arylphosphoramiditegold(I) complexes as catalysts, respectively.