- Discriminating non-ylidic carbon-sulfur bond cleavages of sulfonium ylides for alkylation and arylation reactions
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A sulfonium ylide participated alkylation and arylation under transition-metal free conditions is described. The disparate reaction pattern allowed the separate activation of non-ylidic S-alkyl and S-aryl bond. Under acidic conditions, sulfonium ylides serve as alkyl cation precursors which facilitate the alkylations. While under alkaline conditions, cleavage of non-ylidic S-aryl bond produces O-arylated compounds efficiently. The robustness of the protocols were established by the excellent compatibility of wide variety of substrates including carbohydrates.
- Fang, Jing,Li, Ting,Ma, Xiang,Sun, Jiuchang,Cai, Lei,Chen, Qi,Liao, Zhiwen,Meng, Lingkui,Zeng, Jing,Wan, Qian
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p. 288 - 292
(2021/07/25)
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- Transition-metal-free hydrogenation of aryl halides: From alcohol to aldehyde
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A transition-metal-and catalyst-free hydrogenation of aryl halides, promoted by bases with either aldehydes or alcohols, is described. One equivalent of benzaldehyde affords an equal yield as that of 0.5 equiv of benzyl alcohol. The kinetic study reveals that the initial rate of PhCHO is much faster than that of BnOH, in the ratio of nearly 4:1. The radical trapping experiments indicate the radical nature of this reaction. Based on the kinetic study, trapping and KIE experiments, and control experiments, a tentative mechanism is proposed. As a consequence, a wide range of (hetero)aryl iodides and bromides were efficiently reduced to their corresponding (hetero)arenes. Thus, for the first time, aldehydes are directly used as hydrogen source instead of other well-established alcohol-hydrogen sources.
- Zheng, Hong-Xing,Shan, Xiang-Huan,Qu, Jian-Ping,Kang, Yan-Biao
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supporting information
p. 5114 - 5117
(2017/11/07)
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