A new class of chiral sulfoxideâSchiff base ligands has been developed by the rational combination of two privileged chiral backbones. These sulfoxideâSchiff base ligands were found to be highly efficient for Cu-catalyzed asymmetric Henry reactions (up to 98% yield and 96% ee).
Aminosulf(ox)ides as Ligands for Iridium(I)-Catalyzed Asymmetric Transfer Hydrogenation
作者:Daniëlle G. I. Petra、Paul C. J. Kamer、Anthony L. Spek、Hans E. Schoemaker、Piet W. N. M. van Leeuwen
DOI:10.1021/jo991700t
日期:2000.5.1
series of chiral N,S-chelates (6-22) was synthesized to serve as ligands in the iridium(I)-catalyzed reduction of ketones. Both formic acid and 2-propanol proved to be suitable as hydrogen donors. Sulfoxidation of an (R)-cysteine-based aminosulfide provided a diastereomeric ligand family containing a chiral sulfur atom. The two chiral centers of these ligands showed a clear effect of chiral cooperativity
2-(p-Tolylsulfinyl)benzyl Halides as Efficient Precursors of Optically Pure trans-2,3-Disubstituted Aziridines
作者:Yolanda Arroyo、Ángela Meana、M. Ascensión Sanz-Tejedor、Inés Alonso、José Luis García Ruano
DOI:10.1002/chem.201000217
日期:2010.8.23
Aziridination of (R)‐N‐sulfinylaldimines (aryl, heteroaryl and alkenyl derivatives) with 2‐(p‐tolyl sulfinyl)benzyl iodide in the presence of sodium hexamethyl disilazide takes place with almost complete control of the stereoselectivity (facial and anti/syn) and with very high yields affording opticallypure N‐sulfinyl trans‐2,3‐disubstituted aziridines 7. Simultaneous removal of both C‐ and N‐p‐tolylsulfinyl
在六甲基二硅叠氮化钠存在下,将(R)-N-亚磺酰基醛亚胺(芳基,杂芳基和烯基衍生物)与2-(对甲苯基亚磺酰基)苄基碘叠氮化,几乎可以完全控制立体选择性(面部和反/合成))并以很高的收率提供了光学纯的N-亚磺酰基反式-2,3-二取代的氮丙啶7。同时去除两个C-和ñ - p -tolylsulfinyl基团与吨丁基锂提供了相应的反式-NH氮丙啶8而不会影响它们的光学纯度。一些实验结果表明,这些过程是通过苄基卤代类化合物作为中间体而发展的,而理论计算则支持了苄基碳负离子的形成。这些结果有助于修正2-对甲苯基亚磺酰基苄基碳负离子与亲电试剂反应的机理。
Parallel Kinetic Resolution of Racemic Aldehydes by Use of Asymmetric Horner−Wadsworth−Emmons Reactions
作者:Torben M. Pedersen、Jakob F. Jensen、Rikke E. Humble、Tobias Rein、David Tanner、Kerstin Bodmann、Oliver Reiser
DOI:10.1021/ol991387h
日期:2000.2.1
[reaction: see text] A racemicaldehyde can undergo parallel kinetic resolution (PKR) by simultaneous reaction with two different chiral phosphonates, differing either in the structure of the chiral auxiliary or in the structure of the phosphoryl group (i.e., one (E)- and one (Z)-selective reagent). This strategy allows conversion of a racemicaldehyde to two different, synthetically useful chiral