Showing papers by "Glenn M. Sammis published in 2015"
TL;DR: A three-component carboetherification of unactivated alkenes has been developed allowing the rapid building of complexity from simple starting materials.
Abstract: A three-component carboetherification of unactivated alkenes has been developed allowing the rapid building of complexity from simple starting materials. A wide range of α-substituted styrenes underwent smooth reactions with unactivated alkyl nitriles and alcohols to afford γ-alkoxy alkyl nitriles with concomitant generation of a quaternary carbon center. A radical clock experiment provided clear-cut evidence that the reaction proceeds through a tertiary alkyl radical intermediate.
138 citations
TL;DR: This review presents the newly developed methods for fluorination involving radicals as reactive intermediates and their applications in pharmaceutical, agrochemical, and material chemistry.
Abstract: The importance of fluorinated compounds in pharmaceutical, agrochemical, and material chemistry has led to the development of numerous methods for electrophilic and nucleophilic fluorination. Radical fluorination represents an interesting complementary approach, but it had been limited due to the paucity of selective radical fluorinating agents. The recent uncovering of easier to handle atomic fluorine sources has led to significant advances in radical fluorination in the past few years. This review presents the newly developed methods for fluorination involving radicals as reactive intermediates. 1 Introduction 2 Atomic Fluorine Sources 2.1 Fluorine as a Selective Radical Fluorinating Agent 2.2 Fluoroxy Reagents 2.3 XeF2
2.4 N–F Reagents as Atomic Fluorine Sources 3 Methodologies for Radical Fluorination 3.1 Decarboxylative Fluorination 3.2 Fluorination of Alkenes 3.3 Fluorination of Boronic Acid Derivatives 3.4 C(sp3)–H Fluorination 3.5 C–C Bond Activation 4 Conclusion
73 citations
TL;DR: A novel technique for the synthesis of monofluoromethoxy arenes through the direct fluorodecarboxylation of carboxylic acids was developed that uses photosensitizers and N-fluorobenzenesulfonimide (NFSI).
37 citations
TL;DR: Oxygen atom incorporation leads to a general increase in cyclization diastereoselectivity over carbon analogues and this chemoselective relay cyclization strategy was utilized in the improved synthesis of the tetrahydrofuran fragment in (−)-amphidinolide K.
Abstract: Radical relay cyclizations initiated by alkoxy radicals are a powerful tool for the rapid construction of substituted tetrahydrofurans. The scope of these relay cyclizations has been dramatically increased with the development of two strategies that utilize an oxygen atom in the substrate to accelerate the desired hydrogen atom transfer (HAT) over competing pathways. This has enabled a chemoselective 1,6-HAT over a competing 1,5-HAT. Furthermore, this allows for a chemoselective 1,5-HAT over competing direct cyclizations and β-fragmentations. Oxygen atom incorporation leads to a general increase in cyclization diastereoselectivity over carbon analogues. This chemoselective relay cyclization strategy was utilized in the improved synthesis of the tetrahydrofuran fragment in (−)-amphidinolide K.
32 citations
TL;DR: A review of radical fluorination involving radicals as reactive intermediates can be found in this paper, where the authors present the newly developed methods for fluorination including radical fluorinating agents.
Abstract: The importance of fluorinated compounds in pharmaceutical, agrochemical, and material chemistry has led to the development of numerous methods for electrophilic and nucleophilic fluorination. Radical fluorination represents an interesting complementary approach, but it had been limited due to the paucity of selective radical fluorinating agents. The recent uncovering of easier to handle atomic fluorine sources has led to significant advances in radical fluorination in the past few years. This review presents the newly developed methods for fluorination involving radicals as reactive intermediates. 1 Introduction 2 Atomic Fluorine Sources 2.1 Fluorine as a Selective Radical Fluorinating Agent 2.2 Fluoroxy Reagents 2.3 XeF2
2.4 N–F Reagents as Atomic Fluorine Sources 3 Methodologies for Radical Fluorination 3.1 Decarboxylative Fluorination 3.2 Fluorination of Alkenes 3.3 Fluorination of Boronic Acid Derivatives 3.4 C(sp3)–H Fluorination 3.5 C–C Bond Activation 4 Conclusion
8 citations
TL;DR: A three-component carboetherification of unactivated alkenes has been developed allowing the rapid building of complexity from simple starting materials as discussed by the authors, and a wide range of α-substituted styrenes underwent smooth reactions with unactivated alcohols to afford γ-alkoxy alkyl nitriles with concomitant generation of a quaternary carbon center.
Abstract: A three-component carboetherification of unactivated alkenes has been developed allowing the rapid building of complexity from simple starting materials. A wide range of α-substituted styrenes underwent smooth reactions with unactivated alkyl nitriles and alcohols to afford γ-alkoxy alkyl nitriles with concomitant generation of a quaternary carbon center. A radical clock experiment provided clear-cut evidence that the reaction proceeds through a tertiary alkyl radical intermediate.
1 citations
TL;DR: In this paper, a novel technique for the synthesis of monofluoromethoxy arenes through the direct fluorodecarboxylation of carboxylic acids was developed that uses photosensitizers and N-fluorobenzenesulfonimide (NFSI).
Abstract: Fluorinated methoxy arenes are emerging as important motifs in both agrochemicals and pharmaceuticals. A novel technique for the synthesis of monofluoromethoxy arenes through the direct fluorodecarboxylation of carboxylic acids was developed that uses photosensitizers and N-fluorobenzenesulfonimide (NFSI). Utilization of the oxidatively mild fluorine transfer agent NFSI enabled the synthesis of fluoromethyl ethers that were previously inaccessible with decarboxylative fluorinations performed with Selectfluor. Mechanistic studies are consistent with the photosensitizer effecting oxidation of the aryloxyacetic acid.
1 citations