Nickel-Catalyzed Enantioselective α-Alkenylation of <i>N</i>-Sulfonyl Amines: Modular Access to Chiral α-Branched Amines
作者:Lun Li、Yu-Cheng Liu、Hang Shi
DOI:10.1021/jacs.1c00622
日期:2021.3.24
α-branched amines are common structural motifs in functional materials, pharmaceuticals, and chiral catalysts. Therefore, developing efficient methods for preparing compounds with these privileged scaffolds is an important endeavor in synthetic chemistry. Herein, we describe an atom-economical, modular method for a nickel-catalyzed enantioselective α-alkenylation of readily available linear N-sulfonyl amines
Asymmetric Cyanation of Aldehydes, Ketones, Aldimines, and Ketimines Catalyzed by a Versatile Catalyst Generated from Cinchona Alkaloid, Achiral Substituted 2,2′-Biphenol and Tetraisopropyl Titanate
Full investigation of cyanation of aldehydes, ketones, aldimines and ketimines with trimethylsilyl cyanide (TMSCN) or ethyl cyanoformate (CNCOOEt) as the cyanide source has been accomplished by employing an in situ generated catalyst from cinchona alkaloid, tetraisopropyl titanate [Ti(OiPr)4] and an achiral modified biphenol. With TMSCN as the cyanide source, good to excellent results have been achieved
Gold(I)-Catalyzed Diastereo- and Enantioselective 1,3-Dipolar Cycloaddition and Mannich Reactions of Azlactones
作者:Asa D. Melhado、Giovanni W. Amarante、Z. Jane Wang、Marco Luparia、F. Dean Toste
DOI:10.1021/ja1095045
日期:2011.3.16
reactions with electron-deficient alkenes and N-sulfonyl aldimines to give products of 1,3-dipolar cycloaddition and Mannich addition reactions, respectively. Both of these reactions proceed with good to excellent diastereo- and enantioselectivityusing a single class of gold catalysts, namely C(2)-symmetric bis(phosphinegold(I) carboxylate) complexes. The development of the azlactone Mannich reaction to
Lithiated 4-Isopropyl-3-(methylthiomethyl)-5,5-diphenyloxazolidin-2-one: A Chiral Formyl Anion Equivalent for Enantioselective Preparations of 1,2-Diols, 2-Amino Alcohols, 2-Hydroxy Esters, and 4-Hydroxy-2-alkenoates
作者:Christoph Gaul、Kaspar Schärer、Dieter Seebach
DOI:10.1021/jo0155254
日期:2001.5.1
provide 4-hydroxy-2-alkenoates (Scheme 5). The scope and limitations of the new, overall enantioselective transformation are determined, and the readily recoveredchiralauxiliary used is compared with oxazolidinones of other substitution patterns (Scheme 7). The configuration of a number of products has been assigned by single-crystal X-ray diffraction (cf. Figure 5). These structures and similarities
A Highly Tunable Stereoselective Olefination of Semistabilized Triphenylphosphonium Ylides with <i>N</i>-Sulfonyl Imines
作者:De-Jun Dong、Hai-Hua Li、Shi-Kai Tian
DOI:10.1021/ja910238f
日期:2010.4.14
The Wittigreaction involving direct olefination of triphenylphosphonium ylides (Ph(3)P horizontal lineCHR) with aldehydes is arguably the most often used method for alkene synthesis, but in general it yields mixtures of Z- and E-alkenes for semistabilized triphenylphosphonium ylides (R = aryl or vinyl). We have developed a simple and efficient protocol to improve the stereoselectivity significantly