- Catalytic Asymmetric [3 + 2] Annulation of Hantzsch Esters with Racemic N-Sulfonylaziridines
-
Hantzsch esters (HEs) served as two-carbon partners in a copper(I)-catalyzed enantioselective [3 + 2] annulation with racemic 2-(hetero)aryl-N-sulfonyl aziridines via kinetic resolution to provide pyrrolo[2,3-b]tetrahydropyridines containing multiple contiguous stereogenic centers including all-carbon quaternary centers in excellent yields and enantiopurities and moderate-to-excellent diastereoselectivities. Mainly dependent upon the structures of the aziridines, a competitive hydrogenolysis process with HEs as the hydrogen source was also observed in some cases.
- Chai, Zhuo,Ma, Chen-Xue,Yang, Gaosheng,Yang, Pei-Jun,Zhu, Guo-Sheng
-
supporting information
p. 7933 - 7937
(2021/10/25)
-
- Stereospecific Ring Opening and Cycloisomerization of Aziridines with Propargylamines: Synthesis of Functionalized Piperazines and Tetrahydropyrazines
-
Stereospecific Cu-catalyzed nucleophilic ring opening of N-sulfonylaziridines with propargylamines and subsequent hydroamination afford piperazines, which leads to double-bond isomerization to furnish tetrahydropyrazines. Optically active aziridines can be cross-coupled with high enantiomeric purities (>98% ee).
- Das, Bijay Ketan,Pradhan, Sourav,Punniyamurthy, Tharmalingam
-
supporting information
p. 4444 - 4448
(2018/08/07)
-
- Copper iodide-catalyzed aziridination of alkenes with sulfonamides and sulfamate esters
-
An efficient copper iodide-catalyzed aziridination of a variety of alkenes with sulfonamides and sulfamate esters as the nitrogen source and iodosylbenzene (PhI{double bond, long}O) as the oxidant is reported herein. The reaction is operationally straight
- Chang, Joyce Wei Wei,Ton, Thi My Uyen,Zhang, Zhengyang,Xu, Yanjun,Chan, Philip Wai Hong
-
scheme or table
p. 161 - 164
(2009/04/14)
-
- Imido transfer from bis(imido)ruthenium(VI) porphyrins to hydrocarbons: Effect of imido substituents, C-H bond dissociation energies, and Ru VI/V reduction potentials
-
[RuVI(TMP)(NSO2R)2] (SO2R = Ms, Ts, Bs, Cs, Ns; R = p-C6H4OMe, p-C6H 4Me, C6H5, p-C6H4-Cl, p-C6H4NO2, respectively) and [Ru VI(Por)(NTs)2] (Por = 2,6-Cl2TPP, F 20-TPP) were prepared by the reactions of [RuII(Por)(CO)] with Phl=NSO2R in CH2Cl2. These complexes exhibit reversible RuVI/V couple with E1/2 = -0.41 to -0.12 V vs Cp2Fe+/10 and undergo imido transfer reactions with styrenes, norbornene, cis-cyclooctene, indene, ethylbenzenes, cumene, 9,10-dihydroanthracene, xanthene, cyclohexene, toluene, and tetrahydrofuran to afford aziridines or amides in up to 85% yields. The second-order rate constants (k2) of the aziridination/amidation reactions at 298 K were determined to be (2.6 ± 0.1) × 10-5 to 14.4 ± 0.6 dm3 mol-1 s-1, which generally increase with increasing RuVI/V reduction potential of the imido complexes and decreasing C-H bond dissociation energy (BDE) of the hydrocarbons. A linear correlation was observed between log K (K is the k2 value divided by the number of reactive hydrogens) and BDE and between log k2 and E1/2(RuVI/V); the linearity in the former case supports a H-atom abstraction mechanism. The amidation by [RuVI(TMP)(NNs) 2] reverses the thermodynamic reactivity order cumene > ethylbenzene/toluene, with K(3° C-H)/K(2° C-H) = 0.2 and K(3° C-H)/K(1° C-H) = 0.8.
- Leung, Sarana Ka-Yan,Tsui, Wai-Man,Huang, Jie-Sheng,Che, Chi-Ming,Liang, Jiang-Lin,Zhu, Nianyong
-
p. 16629 - 16640
(2007/10/03)
-
- N-CYCLIC SULFONAMIDO INHIBITORS OF GAMMA SECRETASE
-
The invention provides N-cyclic sulfonamido compounds for use in treating or preventing cognitive disorders, such as Alzheimer’s Disease. Compounds of particular interest are defined by Formula (I), wherein R4, R5, R6, Rs
- -
-
Page/Page column 56
(2010/02/14)
-
- Catalytic asymmetric heterogeneous aziridination of styrene using CuHY: Effect of nitrene donor on enantioselectivity
-
The copper-catalysed aziridination of styrene with copper-exchanged zeolite Y (CuHY) and copper(II) triflate (trifluoromethanesulfonate) (Cu(OTf)2) as catalysts is described in detail. Two nitrene donors, [N-(p-tolylsulfonyl)imino)]phenyliodinane (PhI=NTs) and [N-(p-nitrophenylsulfonyl)imino]phenyliodinane (PhI=NNs) are compared. Modification of the catalyst with bis(oxazolines) affords enantioselective catalysts and a range of chiral bis-(oxazolines) has been studied. The ratio of nitrene donor to styrene is shown to be an important factor controlling both the yield and ee of aziridine formed. The best results are obtained with PhI=NNs; ee, ≥ 90%, together with high yields (≥ 85%), can readily be achieved with this nitrene donor using acetonitrile as solvent. Addition of the nitrene donor over a period of time, rather than all at the start of the reaction, is shown to enhance the yield of the aziridine but the ee is significantly decreased for both the homogeneous and the heterogeneous catalysts. Experiments in which the breakdown products of the nitrene donor, iodobenzene and the corresponding sulfonamide, are added at the star of the reaction show that a complex interplay exists at the copper active site between the reactants, products, chiral modifier and the solvent. However, the heterogeneous catalyst, CuHY, is found to give enhanced enantioselection for a range of bis(oxazolines) compared to the homogeneous catalyst, and the effect is considered to be due to the confinement of the catalyst within the micropores of the zeolite.
- Taylor, Sophia,Gullick, John,McMorn, Paul,Bethell, Donald,Page, Philip C. Bulman,Hancock, Frederick E.,King, Frank,Hutchings, Graham J.
-
p. 1714 - 1723
(2007/10/03)
-
- Methylene Transfer from Dimethyloxosulphonium Methylide to N-Arylsulphonylaziridines: Stereospecific Synthesis of N-Arylsulphonylazetidines
-
Several 2-alkyl, 2-aryl-, 2-benzyl-, 2,3-dialkyl- and 2,3-diarylsulphonylazetidines have been prepared in fair to good isolated yields through reaction of N-arylsulphonylaziridines with dimethyloxosulphonium methylide.Fused azetidines, however, could not
- Nadir, Upender K.,Sharma, Ms. Raman L.,Koul, Veerinder K.
-
p. 2015 - 2020
(2007/10/02)
-