Nickel-Catalyzed Multicomponent Coupling: Synthesis of α-Chiral Ketones by Reductive Hydrocarbonylation of Alkenes
作者:Jian Chen、Shaolin Zhu
DOI:10.1021/jacs.1c07851
日期:2021.9.8
functionalized α-stereocenter, including enantioenriched chiral α-aryl ketones and α-amino ketones. It useschiral bisoxazoline as a ligand, silane as a reductant, chloroformate as a safe CO source, and a racemic secondary benzyl chloride or an N-hydroxyphthalimide (NHP) ester of a protected α-amino acid as the alkylation reagent. The benign nature of this process renders this method suitable for late-stage functionalization
已经开发出一种镍催化、多组分区域选择性和对映选择性偶联,通过顺序加氢甲酰化和羰基化从容易获得的起始材料中进行。这种模块化的多组分加氢官能化策略能够对各种未活化的烯烃进行直接的还原烃基化,以产生各种带有功能化 α-立体中心的不对称二烷基酮,包括对映体富集的手性 α-芳基酮和 α-氨基酮。它使用手性双恶唑啉作为配体,硅烷作为还原剂,氯甲酸酯作为安全的 CO 源,外消旋仲苄基氯或N受保护的 α-氨基酸的 -羟基邻苯二甲酰亚胺 (NHP) 酯作为烷基化试剂。该过程的良性性质使该方法适用于复杂分子的后期功能化。
Lamp versus laser photolysis of 1,3-dichloro-1,3-diphenylpropane in cyclohexane. Direct observation of 1,3-diphenylpropenyl radical
Laserphotolysis of the title compound leads to two-photon processes indicating the involvement of the 1,3-diphenylpropanediyl biradical (12) and the 1,3-diphenylallyl radical (10).
Development of a Catalytic Platform for Nucleophilic Substitution: Cyclopropenone-Catalyzed Chlorodehydration of Alcohols
作者:Christine M. Vanos、Tristan H. Lambert
DOI:10.1002/anie.201104638
日期:2011.12.16
Cyclopropenone makes the switch: 2,3‐Bis‐(p‐methoxyphenyl)cyclopropenone is a highly efficient catalyst for the chlorodehydration of 20 diverse alcohol substrates (see scheme; X=Cl). With oxalyl chloride as catalytic activator, this nucleophilicsubstitution proceeded through cyclopropenium‐activated intermediates and resulted in complete stereochemical inversion in substrates with chiral centers.
环丙烯酮起到了作用:2,3-双(对甲氧基苯基)环丙烯酮是一种高效的催化剂,可对20种不同的醇底物进行氯脱水(参见方案; X = Cl)。用草酰氯作为催化活化剂,这种亲核取代过程通过环丙烯活化的中间体进行,并导致具有手性中心的底物完全立体化学转化。
Oxidatively Intercepting Heck Intermediates: Pd-Catalyzed 1,2- and 1,1-Arylhalogenation of Alkenes
作者:Dipannita Kalyani、Melanie S. Sanford
DOI:10.1021/ja0782798
日期:2008.2.1
communication describes the development of two Pd-catalyzed reactions for the arylchlorination of diverse α-olefins by oxidatively intercepting Heck intermediates. Depending on the nature of the oxidant and the reaction conditions, these transformations can afford synthetically useful 1,1- or 1,2-arylchlorinated products in good yields and with good to excellent selectivities. Preliminary mechanistic
A surface moiety for use in chromatography which is attached to a solid support, said surface moiety having a structure which comprises at least two arylene groups wherein the arylene groups are separated from each other by a hydrocarbylene group. The surface moiety is attached to a solid support to form a stationary phase material. Methods for making the stationary phase material and using the material are provided also as are a chromatography apparatus which contains the material and a surface modifying agent which may be used to attach the surface moiety to the solid support.