An organocatalytic asymmetric sulfenylation of 3-aryloxindoles with N-(sulfanyl)succinimides has been developed by using commercially available (DHQD)2PHAL as catalyst. Various chiral 3-benzylthio-, alkylthio-, and arylthio-substituted oxindoles, containing 3,3-disubstituted quarternary carbon stereocenters, could be obtained in high enantioselectivities (85–97% ee). Furthermore, the opposite enantiomers
Enantioselective Reduction and Sulfenylation of Isoflavanone Derivatives via Bisguanidinium Hypervalent Silicate
作者:Qiaoqiang Li、Yuqing Dai、Xinru Xu、Wentao Wu、Wenchao Chen、Hong Wang、Choon-Hong Tan、Xinyi Ye
DOI:10.1021/acs.orglett.4c02202
日期:2024.7.26
In this work, we describe an enantioselective reduction and sulfenylation of isoflavanone derivatives by an ion pair strategy. The chiral cationic catalyst bisguanidinium (BG) is capable of chiral induction in catalytic systems. Silane hydride works as a reductant and helps to form an anionic hypervalent silicate complex and intermediates with substrates to pair with chiral catalyst. A series of umpolung
An unprecedented asymmetric alpha-sulfenylation of 5H-oxazol-4-ones to N-(sulfanyl)succinimides has been established, to access various alpha-sulfenylated adducts with good to excellent enantioselectivities (86-95% ee) by utilizing a cinchona alkaloid-derived squaramide as catalyst. The conditions of this alpha-sulfenylation protocol simultaneously satisfy N-(arylthio)succinimides, N-(benzylthio)succinimides, and N-(alkylthio)succinimides by tuning the substituted groups of 5H-oxazol-4-ones on the 2-position as well as additives. (C) 2014 Elsevier Ltd. All rights reserved.