90319-52-1Relevant articles and documents
Catalytic enantioselective synthesis of β-amino alcohols by nitrene insertion
Zhou, Zijun,Tan, Yuqi,Shen, Xiang,Ivlev, Sergei,Meggers, Eric
, p. 452 - 458 (2020/12/31)
Chiral β-amino alcohols are important building blocks for the synthesis of drugs, natural products, chiral auxiliaries, chiral ligands and chiral organocatalysts. The catalytic asymmetric β-amination of alcohols offers a direct strategy to access this class of molecules. Herein, we report a general intramolecular C(sp3)-H nitrene insertion method for the synthesis of chiral oxazolidin-2-ones as precursors of chiral β-amino alcohols. Specifically, the ring-closing C(sp3)-H amination of N-benzoyloxycarbamates with 2 mol% of a chiral ruthenium catalyst provides cyclic carbamates in up to 99% yield and with up to 99% ee. The method is applicable to benzylic, allylic, and propargylic C-H bonds and can even be applied to completely non-activated C (sp3)-H bonds, although with somewhat reduced yields and stereoselectivities. The obtained cyclic carbamates can subsequently be hydrolyzed to obtain chiral β-amino alcohols. The method is very practical as the catalyst can be easily synthesized on a gram scale and can be recycled after the reaction for further use. The synthetic value of the new method is demonstrated with the asymmetric synthesis of a chiral oxazolidin-2-one as intermediate for the synthesis of the natural product aurantioclavine and chiral β-amino alcohols that are intermediates for the synthesis of chiral amino acids, indane-derived chiral Box-ligands, and the natural products dihydrohamacanthin A and dragmacidin A.[Figure not available: see fulltext.].
Stereoselective Synthesis of Enantiopure Oxazolidinones via Biocatalytic Asymmetric Aminohydroxylation of Alkenes
Zhou, Xiao-Ying,Wan, Nan-Wei,Li, Ying-Na,Ma, Ran,Cui, Bao-Dong,Han, Wen-Yong,Chen, Yong-Zheng
supporting information, p. 4343 - 4348 (2021/08/03)
Chiral oxazolidinones are of significance in both medicinal and synthetic chemistry, while preparing these compounds usually involves using expensive starting materials and harsh reaction conditions. Herein, a one-pot biocatalytic cascade process was developed for stereo- and regioselective aminohydroxylation of diverse alkenes by combining styrene monooxygenase and halohydrin dehalogenase, providing an approach to enantiopure oxazolidinones. (Figure presented.).
Asymmetric catalysis with a chiral-at-osmium complex
Wang, Guanghui,Zhou, Zijun,Shen, Xiang,Ivlev, Sergei,Meggers, Eric
, p. 7714 - 7717 (2020/07/27)
The first example of a chiral osmium catalyst is reported in which the overall chirality originates exclusively from a stereogenic metal center (metal-centered chirality) with all coordinating ligands being achiral. The non-C2-symmetric chiral-at-metal complex contains two cyclometalated 7-methyl-1,7-phenanthrolinium heterocycles which can be described as two chelating pyridylidene remote N-heterocyclic carbene (rNHC) ligands. The octahedral coordination sphere is completed with one CO and one acetonitrile ligand. A monodentate chiral oxazoline ligand is used as a chiral auxiliary ligand to obtain enantiomerically pure chiral-at-osmium complexes (>99?:?1 e.r.). Finally, it is demonstrated that the developed chiral-at-osmium complex is suitable for ring-closing enantioselective C(sp3)-H aminations, including the first example of catalytic enantioselective cyclizations of azidoformates to chiral 2-oxazolidinones.