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.
Catalytic Asymmetric Michael Addition/Cyclization of Isothiocyanato Oxindoles: Highly Efficient and Versatile Approach for the Synthesis of 3,2′-Pyrrolidinyl Mono- and Bi-spirooxindole Frameworks
作者:Yi-Ming Cao、Fang-Fang Shen、Fu-Ting Zhang、Rui Wang
DOI:10.1002/chem.201204114
日期:2013.1.21
A‐spiro‐ing to greatness: The catalytic asymmetric Michael addition/cyclization of isothiocyanato oxindoles has been realized. This versatile approach provides an easy and highly efficient way to access not only the enantioselective synthesis of 3,2′‐pyrrolidinyl spirooxindole frameworks, but also the construction of enatiomerically enriched bi‐spirooxindoles containingthreecontiguous stereocenters