exo-Selective construction of spiro-[butyrolactone-pyrrolidine] via 1,3-dipolar cycloaddition of azomethine ylides with α-methylene-γ-butyrolactone catalyzed by Cu(I)/DTBM-BIPHEP was written by Li, Qing-Hua;Liu, Tang-Lin;Wei, Liang;Zhou, Xiang;Tao, Hai-Yan;Wang, Chun-Jiang. And the article was included in Chemical Communications (Cambridge, United Kingdom) in 2013.Recommanded Product: 352655-61-9 This article mentions the following:
An expedient access to optically active spiro-[butyrolactone-pyrrolidine] was successfully developed via an unprecedented Cu(I)-catalyzed exo-selective 1,3-DC of azomethine ylides with α-methylene-γ-butyrolactone, which exhibited high diastereoselectivity (>98 : 2), excellent enantioselectivity (96->99% ee) and a broad substrate scope under mild conditions [e.g., N-(4-chlorobenzylidene)glycine Me ester + α-methylene-γ-butyrolactone in presence of Cu(I)/DTBM-BIPHEP afforded I in >98:2 diastereoselectivity and almost perfect enantioselectivity]. In the experiment, the researchers used many compounds, for example, (R)-(-)-2,2′-Bis[di(3,5-di-t-butyl-4-methoxyphenyl)phosphino]-6,6′-dimethoxy-1,1′-biphenyl (cas: 352655-61-9Recommanded Product: 352655-61-9).
(R)-(-)-2,2′-Bis[di(3,5-di-t-butyl-4-methoxyphenyl)phosphino]-6,6′-dimethoxy-1,1′-biphenyl (cas: 352655-61-9) belongs to chiral phosphine ligands. Although many reactions require more nucleophilic trialkylphosphines as catalysts, only a few chiral trialkylphosphines are available. Chiral ligands coordinate to metal centers to create an asymmetric environment around the reaction centers, which eventually affects enantioselectivity and reaction rate.Recommanded Product: 352655-61-9
Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis