- Efficient α-chlorination of carbonyl containing compounds under basic conditions using methyl chlorosulfate
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An efficient method for the α-chlorination of ketones under basic conditions is described using methyl chlorosulfate. Its applicability for the chlorination of other functional groups has also been studied and it is equally useful for the synthesis of α-chloroesters and amides. Methyl chlorosulfate is described for the first time as a positive chlorine source. Some aldol reactions which occur during the chlorination of some substrates are also reported.
- Silva, Saúl,Maycock, Christopher D.
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supporting information
p. 1233 - 1238
(2018/02/27)
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- A Simple and Efficient Method for the Preparation of α-Halogenated Ketones Using Iron(III) Chloride and Iron(III) Bromide as Halogen Sources with Phenyliodonium Diacetate as Oxidant
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α-Halogenated ketones are both unique structure moieties existing in biologically natural products and valuable synthetic intermediates for the preparation of functional molecules. An efficient and scalable method for the preparation of α-halogenated ketone using iron (III) chloride and iron (III) bromide as halogen sources with phenyliodonium diacetate as oxidant has been developed, featuring mild reaction conditions, environmentally friendly reagents, and wide substrate scope. Notably, the three-step synthesis of drug prasugrel was achieved using this developed method as a key step with 30% yield on gram-scale. Additionally, the reaction mechanism involving chloride cation was proposed based on some preliminary control experiments. (Figure presented.).
- Tang, Shi-Zhong,Zhao, Wenshuang,Chen, Tao,Liu, Yang,Zhang, Xiao-Ming,Zhang, Fu-Min
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supporting information
p. 4177 - 4183
(2017/12/18)
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- Oxidative debenzylation of N-benzyl amides and O-benzyl ethers using alkali metal bromide
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The oxidative debenzylation of N-benzyl amides and O-benzyl ethers was promoted with high efficiency by a bromo radical formed through the oxidation of bromide from alkali metal bromide under mild conditions. This reaction provided the corresponding amides from N-benzyl amides and carbonyl compounds from O-benzyl ethers in high yields.
- Moriyama, Katsuhiko,Nakamura, Yu,Togo, Hideo
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supporting information
p. 3812 - 3815
(2014/08/05)
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- Addition of NOCl to cyclic vinylsilanes: An unexpected reversal of regiochemistry
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NOCl adds to cyclic vinylsilanes in a syn manner with NO+ bonding to the β-carbon and Cl- to the α-carbon, which is a reversal of the regiochemistry expected from the β-silicon effect. The adducts dimerize to a single diastereomer containing enantiomeric pairs and/or give secondary products on further reaction.
- Mallya, M. Narendra,Nagendrappa, Gopalpur,Shashidhara Prasad,Sridhar,Lokanath,Begum
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p. 2565 - 2568
(2007/10/03)
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- α-chlorination of ketones using p-toluenesulfonyl chloride
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Treatment of a variety of ketones with lithium diisopropylamide followed by p-toluenesulfonyl chloride gives α-chloroketones in good yields. In addition, a polymer bound tosyl chloride reagent has also been shown to effect this transformation.
- Brummond, Kay M.,Gesenberg, Kirsten D.
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p. 2231 - 2234
(2007/10/03)
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- OXIDATION OF OLEFINS USING CHROMIC ANHYDRIDE-CHLOROTRIMETHYLSILANE. A CONVENIENT SYNTHESIS OF α-CHLORO KETONES.
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Disubstituted internal olefins are oxidized selectively to α-chloro ketones in excellent yields from the reaction with chromic anhydride-chlorotrimethylsilane in carbon tetrachloride.
- Lee, Jong Gun,Ha, Dong Soo
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p. 193 - 196
(2007/10/02)
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- OXYCHLORINATION OF ALKENES BY CHLOROCHROMATE REAGENTS: A FACILE PREPARATION OF α-CHLOROKETONES, AND COMPETITION BY SUBSTITUENT-DIRECTED OXIDATION.
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Cyanopyridinium chlorochromate effects a facile preparation of α-chloroketones from simple alkenes, cycloocta-1,5-diene and cyclododeca-1,5,9-triene; 1-methylcaclooct-4-en-1-ol undergoes oxidative cyclization.
- Guerrero, Angel F.,Kim, Ho-jin,Schlecht, Matthew F.
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p. 6707 - 6710
(2007/10/02)
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- SELECTIVE FAVORSKII REARRANGEMENT IN MACROCYCLIC RINGS
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A mixture of 2,2-dibromo-12-chlorocyclododecanone (IIa) and 2,12-dibromo-2-chlorocyclododecanone (IIb) by Favorskii rearrangement gave selectively methyl 2-chloro-1-cycloundecene-1-carboxylate (IIIa).
- Abad, Antonio,Arno, Manuel,Pedro, Jose R.,Seoane, Eliseo
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p. 1733 - 1736
(2007/10/02)
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- 2-Mercaptocyclododecanone-1
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The fruity flavor of a foodstuff is augmented or enhanced by the use of one or more α-oxy(oxo)mercaptans having the formula: STR1 wherein X is one of: STR2 or STR3 and R1 and R2, taken separately, are the same and are either of methyl, ethyl, 1-propyl or 2-propyl, or R1 and R2 taken together, is nonylene having the structure: STR4 said α-oxy(oxo)mercaptan being selected from the group consisting of: 3-mercapto-4-heptanol; 4-mercapto-5-nonanol; 4-mercapto-5-nonanone; 3-mercapto-2,6-dimethyl-4-heptanone; 2-mercaptocyclododecanone-1; and 2-mercapto-3-pentanone These compounds augment or enhance the green, grapefruit, fruity, buchu leaf oil-like, floral, green vegetable and/or minty aromas and grapefruit-like, green, citrus, bitter, lemon, buchu leaf oil-like, blackcurrant-like, green vegetable-like, and/or cooling notes of food flavors.
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