Enantioselective Synthesis of Cyclic Sulfamidates via Pd-Catalyzed Hydrogenation
摘要:
Using Pd(CF3CO2)(2)/(SS)-f-binaphane as the catalyst, an efficient enantioselective synthesis of cyclic sulfamidates was developed via asymmetric hydrogenation of the corresponding cyclic imines in 2,2,2-trifluoroethanol at room temperature with high enantioselectivities (up to 99% ee).
developed, providing various chiral α-monosubstituted α-aminoacidderivatives with excellent results (97-99% yields, 90 to >99% ee). Cyclic N-sulfonyl ketimines were also hydrogenated well to afford chiral amine derivatives with 98-99% yields and 97 to >99% ee. The gram-scale asymmetric hydrogenation was performed well with 85% yield and 99% ee using only 0.2 mol% catalyst.
Asymmetric Organocatalyzed Reaction Sequence To Synthesize Chiral Bridged and Spiro-Bridged Benzofused Aminals via Divergent Pathways
作者:Ying-Han Chen、Xue-Jiao Lv、Zhi-Hao You、Yan-Kai Liu
DOI:10.1021/acs.orglett.9b01874
日期:2019.7.19
asymmetric organocatalysis-triggered reaction sequence is developed. 2-Hydroxy cinnamaldehydes and cyclic N-sulfonyl ketimines were both used as multisite substrates (more than two reactive sites) to accessstructurallydiverse chiral bridged and spiro-bridged benzofused aminal derivatives, where an inseparable equilibrating mixture of isomers can be regioselectively converted into bridged benzofused
NH<sub>4</sub>OAc-Promoted Domino Route to Hydroxyarylated Unsymmetrical Pyridines under Neat Conditions
作者:Meher Prakash、Santosh K. Gudimella、Rajni Lodhi、Soumitra Guin、Sampak Samanta
DOI:10.1021/acs.joc.9b02896
日期:2020.2.21
domino method has been established for modular synthesis of a diverse range of medicinally promising hydroxyarylated unsymmetrical pyridines in good to high chemical yields with an excellent regioselectivity. This domino process involves a range of N-sulfonyl ketimines as C,N-binucleophiles, enolizable ketones, and aromatic/heteroaromatic aldehydes using ammonium acetate as an ideal promoter under neat
Organocatalytic Enantioselective Formal [4 + 2] Cycloaddition of Enones with Cyclic <i>N</i>-Sulfonylimines and Methylene Chromene for Chiral Spirocyclic Compounds
作者:Jie Fei、Qingqing Qian、Xiaohua Sun、Xiaodong Gu、Chuncheng Zou、Jinxing Ye
DOI:10.1021/acs.orglett.5b02667
日期:2015.11.6
A highly enantioselective synthesis of spirocycles and bridged rings has been developed through a formal [4 + 2] cycloadditionreaction between enones and N-sulfonylimines. The unprecedented strategy has been realized utilizing N-sulfonylimine as a novel dienophile through enamine–iminium tautomerism of N-sulfonylimine. In addition, a γ,ε-regioselective cycloadditionreaction proceeded by employing
An asymmetric domino reaction was developed utilizing readily available cyclic N-sulfonylimines and simplealdehydes to construct biologically important and synthetically challenging piperidine derivatives consisting of three contiguous stereocenters. trans-Perhydroindolic acid proved to be an efficient organocatalyst in this reaction (up to 89% yield, 80:20 dr, and 99% ee). The absolute configuration