the use of different boronic acids, five-, six-, and seven-membered cyclic enones, an unsaturated lactone, and the most challenging acyclic ketones, is reported. An X-ray diffraction study of the [Ferbisox·RhCl]2 precatalyst clearly exhibits a dimeric structure with an S coordination of the sulfoxide to rhodium. On the basis of the X-ray data and on structural studies conducted in solution by 1H NMR
报道了无环C 2对称螯合双亚砜配体在Rh(I)催化的硼酸对电子缺陷烯烃的1,4-加成中的应用。在测试的无环乙烷桥联双亚砜中,配体Ferbisox(11),在亚磺酰基硫基上带有二茂铁基部分作为取代基,在化学收率(最高96%)和对映选择性(最高97%ee)方面表现出最好的结果。室温下,在短时间内(通常为2小时),在甲苯中平稳地进行共轭物加成。据报道,反应范围包括使用不同的硼酸,五元,六元和七元环状烯酮,不饱和内酯和最具挑战性的无环酮。[Ferbisox·RhCl] 2预催化剂的X射线衍射研究清楚显示出亚砜与铑具有S配位的二聚结构。根据X射线数据和在溶液中由1进行的结构研究提出了1 H NMR,其解释了观察到的高对映体的模型。
Asymmetric Umpolung Hydrogenation and Deuteration of Alkenes Catalyzed by Nickel
作者:Siyu Guo、Xiuhua Wang、Jianrong Steve Zhou
DOI:10.1021/acs.orglett.0c00112
日期:2020.2.7
enantioselectivity, using acetic acid or water as the hydrogen source and indium powder as electron donor. The scope of alkenes herein include α,β-unsaturated esters, nitriles, and ketones as well as allylicalcohols. Asymmetric deuteration of α,β-unsaturated esters is also achieved with deuterated water, the cheapest deuterium source.
Regioselective reductions of β,β-disubstituted enones catalyzed by nonracemically ligated copper hydride
作者:Karl R. Voigtritter、Nicholas A. Isley、Ralph Moser、Donald H. Aue、Bruce H. Lipshutz
DOI:10.1016/j.tet.2011.10.056
日期:2012.4
2-additions to β,β-disubstitutedα,β-unsaturatedketones have been further explored. Asymmetric reductions of enones lacking an α-substituent can be achieved with CuH complexed by DTBM-SEGPHOS in Et2O at −25 °C leading to the generation of highly valuable nonracemic allylic alcohols. The corresponding 1,4-reductions can also be achieved using the same reaction conditions by switching the ligand to a JOSIPHOS