- Dehydrative Ring-Opening of gem-Difluorocyclopropyl Carbinols to Allylic Trifluoromethyl and Difluorohalomethyl Derivatives Promated by Titanium Tetrahalide
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We report herein the titanium tetrahalide-promoted dehydrative ring-opening of gem-difluorocyclopropyl carbinols as a novel method for the synthesis of (E)-allylic CF3, (E)-allylic CF2Cl, and (E)-allylic CF2Br compounds. This TiF4-promoted reaction appears to proceed via a concerted SN2' mechanism. A control experiment revealed that the TiCl4-promoted ring-opening initially proceeds by conversion of the gem-difluorocyclopropyl carbinol into a gem-difluorocyclopropyl chloride intermediate.
- Ramasamy, Manickavasakam,Kuo, Sheng-Chu,Hsieh, Min-Tsang
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p. 5207 - 5210
(2020/08/12)
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- Catalytic One-Step Deoxytrifluoromethylation of Alcohols
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A new bench-stable trifluoromethylation reagent, phenyl bromodifluoroacetate, converts readily available alcohols to trifluoromethanes in a Cu-catalyzed deoxytrifluoromethylation reaction. This reaction streamlines access to target biologically active molecules, and should be useful for a variety of medicinal, agricultural, and materials chemists.
- Azambuja, Francisco De,Lovrien, Sydney M.,Ross, Patrick,Ambler, Brett R.,Altman, Ryan A.
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p. 2061 - 2071
(2019/05/16)
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- Copper-catalyzed decarboxylative trifluoromethylation of allylic bromodifluoroacetates
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The development of new synthetic fluorination reactions has important implications in medicinal, agricultural, and materials chemistries. Given the prevalence and accessibility of alcohols, methods to convert alcohols to trifluoromethanes are desirable. However, this transformation typically requires four-step processes, specialty chemicals, and/or stoichiometric metals to access the trifluoromethyl-containing product. A two-step copper-catalyzed decarboxylative protocol for converting allylic alcohols to trifluoromethanes is reported. Preliminary mechanistic studies distinguish this reaction from previously reported Cu-mediated reactions.
- Ambler, Brett R.,Altman, Ryan A.
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supporting information
p. 5578 - 5581
(2013/11/19)
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- Regio- and stereoselective allylic trifluoromethylation and fluorination using CuCF3 and CuF reagents
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Copper-mediated trifluoromethylation of allylic chlorides and trifluoroacetates was performed using a convenient Cu-CF3 reagent. The reaction is suitable for selective synthesis of allyl trifluoromethyl species. Mechanistic studies indicate that the reaction proceeds via a nucleophilic substitution mechanism involving allyl copper intermediates. The analogous Cu-F reagent was suitable for fluorination of allyl chlorides. Stereodefined cyclic substrates reacted regio- and stereoselectively.
- Larsson, Johanna M.,Pathipati, Stalin R.,Szabo, Kalman J.
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p. 7330 - 7336
(2013/08/23)
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