Synthesis and Stereochemical Characterization of Some Optically Active 1,2-Dinaphthylethane-1,2-Diols
摘要:
Three new diols, 1,2-di(2-naphthyl)ethane-1,2-diol, 1-(1-naphthyl)-2-(2-naphthyl)ethane-1,2-diol, and 1,2-di(1-naphthyl)ethane-1,2-diol, have been prepared in optically active form by catalytic asymmetric syn-dihydroxylation of the corresponding (E)-olefins. The complete stereochemical characterization was easily accomplished by transforming them into the corresponding isopropylidene ketals. These derivatives can be separated by HPLC on a Chiralcel OD column allowing the determination of the ee, and at same time, their CD spectra have been analyzed, allowing a safe assignment of absolute configuration in conjunction with molecular mechanics calculations and an exciton-coupling treatment.
Isothiourea-Catalysed Sequential Kinetic Resolution of Acyclic (±)-1,2-Diols
作者:Siegfried Harrer、Mark D. Greenhalgh、Rifahath M. Neyyappadath、Andrew D. Smith
DOI:10.1055/s-0037-1610721
日期:2019.8
The isothiourea-catalysed acylative kineticresolution of a range of acyclic (±)-1,2-diols using 1 mol% of catalyst under operationally simple conditions is reported. Significantly, the bifunctional nature of (±)-1,2-diols was exploited in a sequential double kineticresolution, in which both kineticresolutions operate synergistically to provide access to highly enantioenriched products. The principles
Truly Catalytic and Enantioselective Pinacol Coupling of Aryl Aldehydes Mediated by Chiral Ti(III) Complexes<sup>†</sup>
作者:A. Chatterjee、T. H. Bennur、N. N. Joshi
DOI:10.1021/jo0342875
日期:2003.7.1
A variety of chiral Ti(IV) complexes were reduced in situ with zinc in acetonitrile. The resulting chiral Ti(III) complexes were found to catalyze the pinacol coupling reaction stereoselectively. The best results were obtained from the Ti-SALEN complex, which was found to be an efficient catalyst at 10 mol % concentration. Various aromatic aldehydes were coupled to obtain chiral hydrobenzoin derivatives
Modular chiral polyether podands and their lanthanide complexes
作者:Helen C Aspinall、Nicholas Greeves、Edward G McIver
DOI:10.1016/j.tet.2003.06.008
日期:2003.12
A novel series of modular chiralpolyether podands derivedfromenantiomerically pure hydrobenzoin and binaphthol has been prepared using a NaH/15-crown-5 mediated Williamson ether synthesis. These new homochiral ligands form catalytically active complexes with lanthanide triflates, two of which have been characterised by X-ray diffraction.
Hydrogen Bonding-Assisted Enhancement of the Reaction Rate and Selectivity in the Kinetic Resolution of <i>d,l</i>
-1,2-Diols with Chiral Nucleophilic Catalysts
作者:Kazuki Fujii、Koichi Mitsudo、Hiroki Mandai、Seiji Suga
DOI:10.1002/adsc.201700057
日期:2017.8.17
An extremely efficient acylative kineticresolution of d,l‐1,2‐diols in the presence of only 0.5 mol% of binaphthyl‐based chiral N,N‐4‐dimethylaminopyridine was developed (selectivityfactor of up to 180). Several key experiments revealed that hydrogen bonding between the tert‐alcohol unit(s) of the catalyst and the 1,2‐diol unit of the substrate is critical for accelerating the rate of monoacylation
Catalytic Enantioselective Allyl- and Crotylboration of Aldehydes Using Chiral Diol•SnCl<sub>4</sub> Complexes. Optimization, Substrate Scope and Mechanistic Investigations
作者:Vivek Rauniyar、Huimin Zhai、Dennis G. Hall
DOI:10.1021/ja8016076
日期:2008.7.1
induction in the allylboration of aldehydes by commercially available allylboronic acid pinacol ester 1a. The corresponding homoallylic alcohol products of synthetically useful aliphatic aldehydes are obtained in excellent yields with up to 98:2 er. This combined acid manifold is also efficient in catalyzing the diastereo- and enantioselective crotylboration of aldehydes, thus providing the propionate
我们报告了一类新的 C2 对称手性二醇,其源自对苯二酚骨架。在 Yamamoto 的路易斯酸辅助布朗斯台德酸度(LBA 催化)概念下,这些二醇与 SnCl 4 的组合导致可商购的烯丙基硼酸频哪醇酯 1a 在醛的烯丙基硼化中产生高水平的不对称诱导。合成有用的脂肪醛的相应高烯丙醇产品以高达 98:2 的产率获得。这种组合的酸歧管还可有效催化醛的非对映选择性和对映选择性巴豆基硼化反应,从而提供 >95:5 dr 和高达 98:2 er 的丙酸酯单元。最佳二醇 x SnCl4 配合物 Vivol (4m) x SnCl4 的 X 射线晶体结构,明确显示了这种 LBA 催化剂的 Brønsted 酸性特征及其高度不对称的环境。进一步的控制排除了可能的硼与手性二醇的酯交换机制,并指出频哪醇烯丙基硼酸酯 1 的 LBA 催化剂衍生的活化。由于二醇 x SnCl4 复合物的缓慢解离,需要少量过量的二醇为了抑制由游离