Highly Enantioselective Iridium-Catalyzed Hydrogenation of Conjugated Trisubstituted Enones
作者:Bram B. C. Peters、Jira Jongcharoenkamol、Suppachai Krajangsri、Pher G. Andersson
DOI:10.1021/acs.orglett.0c04012
日期:2021.1.1
Asymmetric hydrogenation of conjugated enones is one of the most efficient and straightforward methods to prepare optically active ketones. In this study, chiral bidentate Ir–N,P complexes were utilized to access these scaffolds for ketones bearing the stereogenic center at both the α- and β-positions. Excellent enantiomeric excesses, of up to 99%, were obtained, accompanied with good to high isolated
A Theoretically-Guided Optimization of a New Family of Modular P,S-Ligands for Iridium-Catalyzed Hydrogenation of Minimally Functionalized Olefins
作者:Jèssica Margalef、Xisco Caldentey、Erik A. Karlsson、Mercè Coll、Javier Mazuela、Oscar Pàmies、Montserrat Diéguez、Miquel A. Pericàs
DOI:10.1002/chem.201402978
日期:2014.9.15
thioether‐phosphite/phosphiniteligands has been evaluated in the asymmetric iridium‐catalyzedhydrogenation of minimallyfunctionalizedolefins. The modular ligand design has been shown to be crucial in finding highly selective catalysts for each substrate. A DFT study of the transition state responsible for the enantiocontrol in the Ir‐catalyzedhydrogenation is also described and used for further optimization
Expanded Scope of the Asymmetric Hydrogenation of Minimally Functionalized Olefins Catalyzed by Iridium Complexes with Phosphite-Thiazoline Ligands
作者:Javier Mazuela、Oscar Pàmies、Montserrat Diéguez
DOI:10.1002/cctc.201300189
日期:2013.8
We have replaced the oxazoline group with a thiazoline moiety in one of the most successful of the phosphite–oxazoline ligand families for the Ir‐catalyzedhydrogenation of minimallyfunctionalizedolefins. A small but structurally important library of Ir phosphite–thiazoline precatalysts (Ir‐L1–L2 a–e) has been developed by changing the substituents/configurations at the biaryl phosphite group. We
我们已经用噻唑啉部分取代了恶唑啉基团,这是亚磷酸酯-恶唑啉配体家族中最成功的一种,用于最小功能化烯烃的Ir催化加氢。通过改变亚磷酸联芳酯基团的取代基/构型,开发了一个小的但在结构上很重要的亚磷酸Ir-噻唑啉预催化剂库(Ir- L1 - L2 a - e)。我们发现在配体设计中用噻唑啉部分取代恶唑啉在底物范围方面是有益的。
Bioreduction of α-Acetoxymethyl Enones: Proposal for an S<sub>N</sub>2′ Mechanism Catalyzed by Enereductase
作者:Bruno R. S. Paula、Davila Zampieri、J. Augusto R. Rodrigues、Paulo J. S. Moran
DOI:10.1002/adsc.201600601
日期:2016.11.17
acylated Morita–Baylis–Hillman adduct 1‐acetoxy‐2‐methylene‐1‐phenylbutan‐3‐one produced a mixture of products, with and without the acetoxygroup, via three different reaction pathways. In addition to experiments employing whole cells, those in which isolated enereductases were used suggested that the main pathway through which the loss of the acetoxygroup occurs during the biocatalytic cascade is an SN2′‐type
(Z)-3-乙酰氧基甲基-4-R-3-丁烯-2-酮(R =芳基,烷基)和(Z)-3-甲基-4-R-3-丁烯-2-丁烯(R =芳基)合成并通过酿酒酵母进行还原,分别产生(R)-和(S)-4-R-3甲基丁烷-2-。这种立体化学控制策略适用于对映体过量至中度过量的(R)-和(S)-Tropional®的合成。其他(Z)-3-酰氧基甲基-4-苯基-3-丁烯-2-酮的行为与(Z)-3-乙酰氧基甲基对应物和酰化的Morita-Baylis-Hillman加合物1-乙酰氧基-2-亚甲基-1-苯基丁烷-3-酮通过三种不同的反应途径生成了带有或不带有乙酰氧基的产物混合物。除了使用全细胞的实验外,使用分离的烯还原酶的实验还表明,在生物催化级联反应中发生乙酰氧基丢失的主要途径是S N 2'型反应,而不是正式的氢加成反应。消除乙酸。最后,相关的乙基烯酮被酵母白色念珠菌对映体选择性还原,产生(R)-和(S)还原产物,取决于起始原料中乙酰氧基的存在。
Substrate scope and synthetic applications of the enantioselective reduction of α-alkyl-β-arylenones mediated by Old Yellow Enzymes
The ene-reductases mediated bioreduction of a selection of open-chain α-alkyl-β-aryl enones afforded the corresponding saturated α-chiral ketones in high yield and optical purity in several cases. The stereo-electronic requirements of the reaction have been investigated, considering the nature and location of substituents on the aromatic ring as well as the steric hindrance at the α-position and adjacent