Synthesis of 7<i>H</i>-Benzo[<i>e</i>]naphtho[1,8-<i>bc</i>]silines by Rhodium-catalyzed [2 + 2 + 2] Cycloaddition
作者:Takumi Maesato、Ryo Shintani
DOI:10.1246/cl.200025
日期:2020.4.5
An efficient synthesis of 7H-benzo[e]naphtho[1,8-bc]silines has been developed by a rhodium-catalyzed [2 + 2 + 2] cycloaddition of alkynyl(8-alkynyl-1-naphthyl)silanes with internal alkynes. High c...
Development of Effective Bidentate Diphosphine Ligands of Ruthenium Catalysts toward Practical Hydrogenation of Carboxylic Acids
作者:Shota Yoshioka、Ke Wen、Susumu Saito
DOI:10.1246/bcsj.20210023
日期:2021.5.15
represents one of the most ideal reduction methods for utilizing abundant CAs as alternative carbon and energy sources. However, systematic studies on the effects of metal-to-ligand relationships on the catalytic activity of metal complex catalysts are scarce. We previously demonstrated a rational methodology for CA hydrogenation, in which CA-derived cationic metal carboxylate [(PP)M(OCOR)]+ (M = Ru and Re;
将羧酸(CA)加氢成醇代表了最理想的还原方法之一,该方法可利用丰富的CA作为替代碳和能源。但是,关于金属与配体之间的关系对金属络合物催化剂催化活性的影响的系统研究很少。我们之前展示了一种合理的CA加氢方法,其中CA衍生的阳离子金属羧酸盐[(PP)M(OCOR)] +(M = Ru和Re; P =一个P配位)用作CA自诱导的CA氢化的催化剂原型。本文中,我们报告了有关如何通过修饰分子Ru催化剂的双齿二膦(PP)配体结构来实现更高催化活性的系统试验研究。连接两个P原子以及PP配体的P原子上取代的Ar基的碳链发生剧烈变化,并且从预催化剂Ru(acac)3诱导了活性Ru催化剂被广泛调查。结果,(PP)Ru催化剂的活性和耐用性与其他分子式Ru催化剂体系(包括我们的原始Ru催化剂)相比大大提高了。结果证实了我们改进催化剂性能的方法,这将有利于CA自诱导CA加氢的进一步发展。
Ruthenium-Catalyzed Regio- and Enantioselective Allylic Substitution with Water: Direct Synthesis of Chiral Allylic Alcohols
作者:Naoya Kanbayashi、Kiyotaka Onitsuka
DOI:10.1002/anie.201101078
日期:2011.5.23
Less is more: A new route to access chiralallylic alcohols through the regio‐ and enantioselectivesubstitution of monosubstituted allylic chlorides with water has been developed. The reaction is catalyzed effectively by planar‐chiral cyclopentadienyl ruthenium complexes (see scheme).
Chiral spiro diphosphines (SDP) are efficient ligands for the Pd-catalyzed asymmetric allylicalkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate and related nucleophiles. The newly synthesized ligand DMM-SDP (1e) with 3,5-dimethyl-4-methoxy groups on the P-phenyl rings of the phosphine shows the highest enantioselectivity (up to 99.1% ee). Diethylzinc as a base is critical for obtaining
Asymmetric Organocatalytic Conjugate Addition of Diarylphosphane Oxides to Chalcones
作者:Alessio Russo、Alessandra Lattanzi
DOI:10.1002/ejoc.201001308
日期:2010.12
The first example of a convenient and enantioselective asymmetric conjugateaddition of diarylphosphane oxides to chalcones is reported. By using commercially available dihydroquinine as the organocatalyst and diphenylphosphane oxide as the nucleophile, the adducts were isolated in high yield and up to 89 % ee. The final adducts can be easily recrystallized to enantiopure material.
报告了二芳基膦氧化物与查耳酮的方便和对映选择性不对称共轭加成的第一个例子。通过使用市售的二氢奎宁作为有机催化剂和二苯基氧化膦作为亲核试剂,以高产率和高达 89% ee 分离出加合物。最终的加合物可以很容易地重结晶为对映体纯材料。