Quinine as an organocatalytic dual activator for the diastereoselective synthesis of spiro-epoxyoxindoles
摘要:
A highly efficient organocatalytic approach has been developed for the diastereoselective epoxidation of (E)-3-ylidene-indolin-2-one derivatives using readily available natural product quinine and urea-hydrogen peroxide (UHP) in DCM at 10 degrees C to afford trans spiro-epoxyoxindoles which were further utilized to obtain beta-hydroxy-alpha-amino esters by water mediated regioselective ring opening from the less hindered end with aniline derivatives, under sonication. (C) 2013 Elsevier Ltd. All rights reserved.
Quinine as an organocatalytic dual activator for the diastereoselective synthesis of spiro-epoxyoxindoles
摘要:
A highly efficient organocatalytic approach has been developed for the diastereoselective epoxidation of (E)-3-ylidene-indolin-2-one derivatives using readily available natural product quinine and urea-hydrogen peroxide (UHP) in DCM at 10 degrees C to afford trans spiro-epoxyoxindoles which were further utilized to obtain beta-hydroxy-alpha-amino esters by water mediated regioselective ring opening from the less hindered end with aniline derivatives, under sonication. (C) 2013 Elsevier Ltd. All rights reserved.
The asymmetricepoxidation of 2‐oxoindoline‐3‐ylidene acetaldehydes, catalyzed by diarylprolinol silyl ether, has been developed. The reaction provides oxindole derivatives possessing chiral epoxides in good yield with good diastereoselectivity and excellent enantioselectivity.
A novel asymmetric nucleophilic epoxidation for alpha-ylideneoxindole esters has been successfully devised, resulting in enantioenriched spiro compounds with two new contiguous stereocenters. The employed (S)-alpha,alpha-diphenylprolinol functions as a bifunctional catalyst, creating a complex H-bond network in conjunction with a substrate and an oxidant.
Baiocchi, Leandro; Giannangeli, Marilena, Journal of Heterocyclic Chemistry, 1988, vol. 25, p. 1905 - 1909
作者:Baiocchi, Leandro、Giannangeli, Marilena
DOI:——
日期:——
Quinine as an organocatalytic dual activator for the diastereoselective synthesis of spiro-epoxyoxindoles
作者:Mangilal Chouhan、Anang Pal、Ratnesh Sharma、Vipin A. Nair
DOI:10.1016/j.tetlet.2013.10.115
日期:2013.12
A highly efficient organocatalytic approach has been developed for the diastereoselective epoxidation of (E)-3-ylidene-indolin-2-one derivatives using readily available natural product quinine and urea-hydrogen peroxide (UHP) in DCM at 10 degrees C to afford trans spiro-epoxyoxindoles which were further utilized to obtain beta-hydroxy-alpha-amino esters by water mediated regioselective ring opening from the less hindered end with aniline derivatives, under sonication. (C) 2013 Elsevier Ltd. All rights reserved.