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.
Synthesis of spirocyclic oxazole derivatives from 2-arylidene cycloalkanones and α-halohydroxamates
作者:Huiyang Wan、Shuangshuang Xia、Xinghua Liu、Yongchan Jian、Yuanyuan An、Yubin Wang
DOI:10.1039/d2ob00701k
日期:——
Herein we disclose a facile route to spirocyclic oxazolederivatives via [3 + 2] cycloaddition reactions between 2-arylidene cycloalkanones and azaoxyallyl cations that formed in situ from α-halohydroxamates in the presence of base. This methodology was shown to lead to an efficient formation of a series of functionalized spirocyclic oxazolederivatives in good to excellent yields.
Proline and secondary amine co-catalyzed condensation of cyclobutanone with aldehydes: a facile access to 2-methylenecyclobutanones under near neutral conditions
作者:Lei Yu、Jie Luan、Lin Xu、Yuanhua Ding、Qing Xu
DOI:10.1016/j.tetlet.2015.09.088
日期:2015.10
Using L-proline catalyst, the useful building blocks 2-methylenecyclobutanones (2-MCBones) are now easily accessible in moderate to good yields through the condensation of the commercially available cyclobutanone with the abundant aldehydes. Compared with the literature reports, this methodology provides a direct synthesis of 2-MCBones from accessible starting materials and employs near neutral catalysts, which are stable to the acidic impurities in substrates. (C) 2015 Elsevier Ltd. All rights reserved.