- Phthalide synthesis through dehydrogenated lactonization of the C(sp3)-H bond by photoredox catalysis
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A practical and efficient method is established for the direct oxidative lactonization of the C(sp3)-H bonds relying on visible-light-induced photoredox catalysis. This protocol expediently allows the delivery of diverse phthalides using oxygen as the sole terminal oxidant under metal-free conditions at room temperature. Notably, the choice of an appropriate hydrogen atom transfer (HAT) cocatalyst is revealed to be critical for the success of this process.
- Cai, Shunyou,Cai, Zhixiong,Chen, Shanyi,Huang, Mingqiang,Lai, Qihong,Lin, Yulin,Liu, Chao,Liu, Hui
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p. 8212 - 8216
(2021/10/29)
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- Visible Light-Promoted Magnesium, Iron, and Nickel Catalysis Enabling C(sp3)-H Lactonization of 2-Alkylbenzoic Acids
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A mild and practical C(sp3)-H lactonization protocol has been achieved by merging photocatalysis and magnesium (iron, nickel) catalysis. A diverse range of 2-alkylbenzoic acids with a variety of substitution patterns could be transformed into the corresponding phthalide products. Based on the mechanistic experimentation and reported prior studies, a possible mechanism for the benzylic oxidative lactonization reaction was proposed with the hypothetic photoactive ternary complex formed between the 2-alkylbenzoic acid substrate, magnesium ion, and bromate anion.
- Li, Sasa,Su, Mincong,Sun, Jie,Hu, Kunjun,Jin, Jian
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supporting information
p. 5842 - 5847
(2021/07/31)
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- Facile synthesis of phthalides from methyl ortho-iodobenzoates and ketones via an iodinemagnesium exchange reaction using a silylmethyl Grignard reagent
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Phthalides have been easily prepared by the treatment of methyl o-iodobenzoates with a silylmethyl Grignard reagent in the presence of ketones. The electron-withdrawing ester moiety of methyl o-iodobenzoates and the low nucleophilicity of the silylmethyl Grignard reagent prompted a smooth iodinemagnesium exchange reaction, at room temperature, without affecting the ester moiety or resulting in an undesired reaction with electrophilic ketones. This simple method, wherein special control of the reaction temperature was unnecessary, has allowed the synthesis of various phthalides, including a phenolphthalein derivative.
- Nakamura, Yu,Yoshida, Suguru,Hosoya, Takamitsu
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supporting information
p. 858 - 861
(2017/06/13)
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