EnantiopureC1-Symmetric Bis(imino)pyridine Cobalt Complexes for Asymmetric Alkene Hydrogenation
摘要:
Enantiopure C-1-symmetric bis(imino)pyridine cobalt chloride, methyl, hydride, and cyclometalated complexes have been synthesized and characterized. These complexes are active as catalysts for the enantioselective hydrogenation of geminal-disubstituted olefins.
hydrogenation of unfunctionalized aryl-substituted olefins with iridium-phosphanyldihydrooxazole complexes 1 (see reaction scheme). The anion of the complex-for example, hexafluorophosphate or tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BARF- )-has a remarkable effect on the reactivity and longevity of the catalyst.
Chiral (iminophosphoranyl)ferrocenes: highly efficient ligands for rhodium- and iridium-catalyzed enantioselective hydrogenation of unfunctionalized olefins
作者:Thanh Thien Co、Tae-Jeong Kim
DOI:10.1039/b607450b
日期:——
A series of chiral (iminophosphoranyl)ferrocenes (1-3) are highly efficient ligands for Rh- and Ir-catalyzed hydrogenation of a number of unfunctionalized olefins; almost perfect enantiomeric excesses (up to 99% ee) have been achieved under mild reaction conditions.
Extending the Substrate Scope in the Hydrogenation of Unfunctionalized Tetrasubstituted Olefins with Ir-P Stereogenic Aminophosphine–Oxazoline Catalysts
作者:Maria Biosca、Ernest Salomó、Pol de la Cruz-Sánchez、Antoni Riera、Xavier Verdaguer、Oscar Pàmies、Montserrat Diéguez
DOI:10.1021/acs.orglett.8b04084
日期:2019.2.1
MaxPHOX-type ligands have been successfully applied in the challenging asymmetrichydrogenation of tetrasubstitutedolefins under mild reaction conditions. Gratifyingly, these catalyst precursors are able to efficiently hydrogenate not only a range of indene derivatives (ee’s up to 96%) but also 1,2-dihydronapthalene derivatives and acyclic olefins (ee’s up to 99%), which both constitute the most challenging
Iridium-Catalyzed Asymmetric Transfer Hydrogenation of 1-Aryl-1-alkylethenes with Ethanol
作者:Xixia Tang、Lu Qian、Guixia Liu、Zheng Huang
DOI:10.1021/acs.orglett.3c01880
日期:2023.7.7
Asymmetric transfer hydrogenation of 1-aryl-1-alkylethenes with ethanol was developed with a chiral (PCN)Ir complex as the precatalyst, featuring high enantioselectivities, good functional group tolerance, and operational simplicity. The method is further applied to formal intramolecular asymmetric transfer hydrogenation of alkenols without an external H-donor, producing a tertiary stereocenter and
以手性(PCN)Ir配合物为预催化剂,开发了1-芳基-1-烷基乙烯与乙醇的不对称转移氢化反应,具有对映选择性高、官能团耐受性好、操作简单等特点。该方法进一步应用于无需外部氢供体的烯醇的正式分子内不对称转移氢化,同时产生叔立构中心和远程酮基。克级合成和( R )-黄根醇关键前体的合成凸显了催化系统的实用性。
Discrimination of the Enantiotopic Faces of Structurally Unbiased Carbenium Ions Employing a Cyclohexadiene‐Based Chiral Hydride Source
A chiral cyclohexadiene-based dihydrogen surrogate can distinguish between the enantiotopic faces of benzylic carbenium ions (see Scheme). No covalent interactions are required but instead dispersion controls the facial discrimination as verified by computations.