Synthesis of 2-(2-Oxo-2-phenylethyl)cyclopentanone by Rhodium-Catalyzed Tandem Alkynyl Cyclobutanols Hydroacylation and Semipinacol Rearrangement
作者:Rui Guo、Xueling Mo、Guozhu Zhang
DOI:10.1021/acs.orglett.8b03973
日期:2019.3.1
A rhodium-catalyzed tandem reaction of alkynyl cyclobutanols with salicylaldehydes has been developed. The reaction offers a new and atom-economical approach for the selective preparation of multisubstituted 2-(2-oxo-2-phenylethyl)cyclopentanone in high yields under mild reaction conditions with tolerance of a broad range of substituted alkynyl cyclobutanols and salicylaldehyes. The isolation of intermediate
Ir-Catalyzed Asymmetric Hydrogenation of α-Alkylidene β-Lactams and Cyclobutanones
作者:Jingzhao Xia、Yu Nie、Guoqiang Yang、Yangang Liu、Ilya D. Gridnev、Wanbin Zhang
DOI:10.1002/cjoc.201800088
日期:2018.7
Chiral β‐lactams and cyclobutanones are present in numerous natural and pharmaceutical products. The stereoselective construction of chiral four‐membered cyclic compounds is an ongoing challenge for the chemical community. Herein, we report a highly stereocontrolled construction of four‐membered ring (mini‐sized) β‐lactams and cyclobutanones via an Ir/In‐BiphPHOX‐catalyzed asymmetric hydrogenation
许多天然和药物产品中都存在手性β-内酰胺和环丁酮。手性四元环化合物的立体选择性结构是化学界面临的挑战。本文中,我们报告了通过Ir / In-BiphPHOX催化的不对称加氢对四元环(微型)β-内酰胺和环丁酮进行高度立体控制的结构,从而提供了相应的旋光四元环羰基产物,这些产物带有α-手性碳中心,在温和的反应条件下(1.0-2.5 bar H 2)具有出色的收率(高达99%)和对映选择性(高达98%)持续1.0-10小时)。该反应代表了广泛的底物范围。还进行了催化产物的多种转化,以显示该方案的潜在效用。
Facile synthesis of 2-methylenecyclobutanones via Ca(OH)<sub>2</sub>-catalyzed direct condensation of cyclobutanone with aldehydes and (PhSe)<sub>2</sub>-catalyzed Baeyer–Villiger oxidation to 4-methylenebutanolides
(2-MCBones), used to be difficult to access, but can now be easily achieved by a green and stereospecific Ca(OH)2-catalyzed direct and simple aldol condensation of cyclobutanone and aldehydes under mild conditions. The obtained (E)-2-MCBones should be a class of potentially useful building blocks in synthesis as they could readily undergo an interesting (PhSe)2-catalyzed Baeyer–Villiger (BV) oxidation
2-亚甲基环丁酮(2-MCBones)过去很难获得,但现在可以通过在绿色和立体定向Ca(OH)2催化下在温和条件下环丁酮和醛的直接简单的羟醛缩合直接实现。所获得的(E)-2-MCBones应该是一类在合成中潜在有用的结构单元,因为它们在室温下很容易通过H 2 O 2进行有趣的(PhSe)2催化的Bayerer -Villiger(BV)氧化而得到通用的4-亚甲基丁醇化物。机理研究表明,BV反应最有可能通过苯硒代过氧苯甲酸酐[PhSe(O)O] 2的初步形成而进行。O然后转化为苯硒酸过氧酸PhSe(O)OOH作为活性氧化剂,然后将其选择性添加到2-MCBones的C O键中,然后进行选择性的C-C键裂解和重排,得到4-亚甲基丁醇化物。
Selective Asymmetric Hydrogenation of Four-Membered <i>Exo</i>-α,β-Unsaturated Cyclobutanones Using RuPHOX–Ru as a Catalyst
The selective asymmetric hydrogenation of four-membered exo-α,β-unsaturated cyclobutanones has been achieved for the first time using RuPHOX-Ru as a catalyst, providing four-membered exo-cyclic chiral allylic alcohols in high yields and with up to 99.9% ee. The reaction could be performed on a gram scale with a relatively low catalyst loading (up to 10000 S/C), and the resulting products can be transformed
使用RuPHOX-Ru作为催化剂,首次实现了四元外-α,β-不饱和环丁酮的选择性不对称加氢,以高收率和高达99.9%的产率提供了四元外环手性烯丙基醇。 ee。该反应可以以克级进行,具有相对较低的催化剂负载量(最高10000 S / C),并且所得产物可以转化为几个生物活性分子。
Rh(I)-catalyzed ring-opening of cyclobutanols via C–C bond activation: Synthesis of cis-olefin with a remote aldehyde
作者:Yu Nie、Jianzhong Chen、Wanbin Zhang
DOI:10.1016/j.tet.2019.130563
日期:2019.9
A Rh(I)-catalyzed ring-opening of cyclobutanols has been developed with ring opening products bearing cis-olefin and a remote aldehyde. Various substrates bearing different substituted aryl groups, heterocyclic groups and alkyl groups were compatible with the mild reaction conditions. A β-C elimination pathway was proposed based on the results of preliminary mechanistic studies.