A Highly<i>anti</i>-Selective Asymmetric Henry Reaction Catalyzed by a Chiral Copper Complex: Applications to the Syntheses of (+)-Spisulosine and a Pyrroloisoquinoline Derivative
作者:Kun Xu、Guoyin Lai、Zhenggen Zha、Susu Pan、Huanwen Chen、Zhiyong Wang
DOI:10.1002/chem.201201775
日期:2012.9.24
A highly anti‐selective asymmetricHenryreaction has been developed, affording synthetically versatile β‐nitroalcohols in a predominately anti‐selective manner (mostly above 15:1) and excellent ee values (mostly above 95 %). Moreover, the anti‐selective Henryreaction was carried out in the presence of water for the first time with up to 99 % ee. The catalytic mechanism was proposed based on the detection
A general synthesis of 5-unsubstitutedbenzylpyrrole-2-carboxylates was developed based on the reaction of β-nitroacetates with benzylisocyanoacetate. The advantage of this route over other pyrrole syntheses was the regiochemical control of the substitution pattern on the pyrrole ring.
catalysts based on Al2O3, supercritical carbon dioxide not only acts as a good solvent for the reaction of aromatic and aliphaticaldehydes with 1-nitroalkanes but, most importantly, it also allows the selectivity to be tuned between the competitive formation of beta-nitroalcohols and nitroalkenes (from the Henry reaction and the nitroaldol condensation, respectively). In particular, when the pressure
A Highly Diastereo- and Enantioselective Copper(I)-Catalyzed Henry Reaction Using a Bis(sulfonamide)−Diamine Ligand
作者:Wei Jin、Xincheng Li、Boshun Wan
DOI:10.1021/jo101932a
日期:2011.1.21
bis(sulfonamide)−diamine (BSDA) ligands were synthesized from commercially available chiral α-amino alcohols and diamines. The chiral BSDA ligand 3a, coordinated with Cu(I), catalyzes the enantioselective Henry reaction with excellent enantioselectivity (up to 99%). Moreover, with the assistance of pyridine, a CuBr−3a system promotes the diastereoselective Henry reaction with various aldehyde substrates
the N2Cl3 coordination sphere around copper(II) is distorted square pyramidal in nature in 2-OCH3. Isolated 2-R complexes, on dissolution in methanol, are found to undergo facile reduction of the metal center to generate the corresponding 1-R complexes. The 1-R and 2-R complexes show intense absorptions in the visible and ultraviolet regions. Cyclic voltammetry on the 1-R and 2-R complexes shows both
摘要1,4-二氮杂丁二烯(p-RC6H4N = C(H)(H)C = NC6H4R-p; R = OCH3,CH3,H和Cl;缩写为LR)在环境温度下于甲醇中与CuCl2·2H2O反应25°C)提供一组[CuI(LR)Cl} 2]类型的双氯桥联双铜配合物,命名为1-R。在乙腈中进行的类似反应提供了一种类型为[CuII(LR)Cl2} 2]的双氯桥联双铜络合物,称为2-R。1-OCH3和2-OCH3的分子结构已经通过X射线晶体学确定。虽然铜(I)在1-OCH3中具有接近四面体的N2Cl2配位球,但铜(II)周围的N2Cl3配位球在2-OCH3中实际上是扭曲的方形锥体。分离的2-R配合物,溶于甲醇后,被发现容易地还原金属中心以生成相应的1-R配合物。1-R和2-R配合物在可见光和紫外线区域显示出强烈的吸收。1-R和2-R配合物的循环伏安法显示了以金属为中心和以配体为中心的氧化还原反应。发现