- Pummerer Synthesis of Chromanes Reveals a Competition between Cyclization and Reductive Chlorination
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The competition between an unprecedented reductive chlorination and the Pummerer reaction was studied and applied to the synthesis of benzofused oxygen heterocycles including 3-aminochromanes and in the intramolecular chlorination of activated aromatic ri
- Acosta-Guzmán, Paola,Rodríguez-López, Alvaro,Gamba-Sánchez, Diego
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p. 6903 - 6908
(2019/09/30)
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- Diverse ring opening of thietanes and other cyclic sulfides: An electrophilic aryne activation approach
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Organosulfides are a common class of structure units in bioactive molecules and functional materials motivating continuous developments of efficient synthetic methods. Herein, we report an electrophilic aryne-activated ring opening protocol of one or two
- Zheng, Tianyu,Tan, Jiajing,Fan, Rong,Su, Shuaisong,Liu, Binbin,Tan, Chen,Xu, Kun
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supporting information
p. 1303 - 1306
(2018/02/14)
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- Gold-Catalyzed Anti-Markovnikov Selective Hydrothiolation of Unactivated Alkenes
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Despite the widespread use of transition-metal catalysts in organic synthesis, transition-metal-catalyzed reactions of organosulfur compounds, which are known as catalyst poisons, have been difficult. In particular, the transition-metal-catalyzed addition of organosulfur compounds to unactivated alkenes remains a challenge. A novel gold-catalyzed hydrothiolation of unactivated alkenes is presented, which proceeds effectively to give the anti-Markovnikov-selective adducts in good yields and in a regioselective manner.
- Tamai, Taichi,Fujiwara, Keiko,Higashimae, Shinya,Nomoto, Akihiro,Ogawa, Akiya
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supporting information
p. 2114 - 2117
(2016/06/01)
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- Silica: An efficient catalyst for one-pot regioselective synthesis of dithioethers
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The development of a silica-promoted highly selective synthesis of 1,2 or 1,3-dithioethers via solvent-free one-pot tandem reactions of an allyl bromide with excess thiol at room temperature is described. The choice of silica gel, either pre-calcined or moistened with water, exhibited notable regioselectivity in the formation of dithioethers. Plausible mechanistic routes were explored and postulated.
- Kundu, Samir,Roy, Babli,Basu, Basudeb
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- Dendrimeric organochalcogen catalysts for the activation of hydrogen peroxide: Improved catalytic activity through statistical effects and cooperativity in successive generations
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Dendrimeric polyphenylsulfides, -selenides, and -tellurides are prepared in high yield using propyloxy spacers to connect the phenylchalcogeno groups to the dendrimeric core. The selenides and tellurides catalyze the oxidation of bromide with hydrogen peroxide to give positive bromine species that can be captured by cyclohexene in two-phase systems. The corresponding sulfides show no catalytic activity. The increase in the rate of catalysis followed statistical effects for 1, 6, and 12 phenyltelluro groups. However, the increase in the rate of catalysis exceeds statistical contributions for the first few generations with 1, 3, 6, and 12 phenylseleno groups and suggested cooperativity among phenylseleno groups. The increase in catalytic rate was lost upon replacing all but one phenylseleno group with phenoxy groups. On the basis of H2O2 consumed, the dendrimer with 12 phenylseleno groups has a turnover number of >60 000 mol of H2O2 consumed per mole of catalyst.
- Francavilla,Drake,Bright,Detty
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