exclusive asymmetric reduction of CO bonds of 2-arylidene four-, five-, six-, and seven-membered cycloalkanones has been studied systematically. The asymmetric transfer hydrogenation was performed using a robust and commercially available chiral diamine-derived ruthenium complex as a catalyst and HCOOH/Et3N as a hydrogen source under mild conditions, giving 51 examples of chiral exocyclic allylic alcohols
已经系统地研究了2-芳基四,五,六和七元环烷烃的C O键的排他不对称还原。在温和条件下,使用稳固且可商购的手性二胺衍生钌络合物作为催化剂,HCOOH / Et 3 N作为氢源,进行不对称转移氢化,给出了51种示例手性环外烯丙基醇,收率高达96%, 99%ee。该方法也适用于抗炎洛索洛芬和天然产物(-)-goniomitine的活性中间体的克级合成。
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.
Rhodium(I)‐Catalyzed [4 + 2] Cycloaddition Reactions of 2‐Alkylenecyclo‐butanols with Alkynes and (<i>E</i>)‐2‐Nitroethenylbenzene through C(sp<sup>2</sup>)—C(sp<sup>3</sup>) Bond Cleavage
作者:Xinxin Zheng、Guozhu Zhang、Dayong Zhang
DOI:10.1002/cjoc.201900082
日期:2019.8
An intermolecular [4 + 2] cycloaddition was realized through C—C bond cleavage in the presence of Rh(I) catalyst. The selective ring opening of 2‐alkylenecyclobutanols enables the generation of active alkenylrhodium species, which underwent smooth cross addition over alkynes and (E)‐2‐nitroethenylbenzene, leading to highly substituted all‐carbon six‐membered rings in a single step and in a complete
Radical-induced ring-opening and reconstruction of cyclobutanone oxime esters
作者:Panpan Wang、Binlin Zhao、Yu Yuan、Zhuangzhi Shi
DOI:10.1039/c8cc10109d
日期:——
The first example of intramolecular ring-opening and reconstruction of cyclobutanone oxime esters via selective C–C bond cleavage leading to the synthesis of 3,4-dihydronaphthalene-2-carbonitriles in the presence of a cheap copper catalyst has been reported. The protocol is distinguished by mild and safe reaction conditions that exclude ligands, oxidants, bases, toxic cyanide salts and tolerates a