Sulfamides direct radical-mediated chlorination of aliphatic C–H bonds

Short, Melanie A.; Shehata, Mina F.; Sanders, Matthew A.; Roizen, Jennifer L.

doi:10.1039/c9sc03428e

Cited by 36 publications

(19 citation statements)

References 64 publications

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“…Contemporaneous to the research disclosed by the groups of Muñiz and Minakata, our laboratory has revealed the generality of sulfamide substrates to guide 1,6-HAT processes by developing a mechanistically straightforward chlorine-transfer reaction (Scheme 31 and Scheme 32). 49 Similar to sulfamate esters, we have found that sulfamidemasked amines and amides are effective directing groups for functionalization of remote C(sp 3 )-H bonds. 50 In these investigations, we have observed that sulfamidyl radicals are capable of abstracting C(sp 3 )-H bonds from primary, secondary, and tertiary centers to provide the corresponding alkyl chlorides in remarkable yields.…”

Section: Synpacts Syn Lettmentioning

confidence: 81%

Modifying Positional Selectivity in C–H Functionalization Reactions with Nitrogen-Centered Radicals: Generalizable Approaches to 1,6-Hydrogen-Atom Transfer Processes

Short¹,

Blackburn²,

Roizen³

2019

Synlett

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Nitrogen-centered radicals are powerful reaction intermediates owing in part to their ability to guide position-selective C(sp3)–H functionalization reactions. Typically, these reactive species dictate the site of functionalization by preferentially engaging in 1,5-hydrogen-atom transfer (1,5-HAT) processes. Broadly relevant approaches to alter the site-selectivity of HAT pathways would be valuable because they could be paired with a variety of tactics to install diverse functional groups. Yet, until recently, there have been no generalizable strategies to modify the position-selectivity observed in these HAT processes. This Synpacts article reviews transformations in which nitrogen-centered radicals preferentially react through 1,6-HAT pathways. Specific attention will be focused on strategies that employ alcohol- and amine-anchored sulfamate esters and sulfamides as templates to achieve otherwise rare γ-selective functionalization reactions.1 Introduction2 Transformations that Rely on Structural Constraints or Weakened C–H Bonds to Favor 1,6-HAT Processes3 Sulfamate Esters Engage Selective 1,6-HAT Processes4 Expansion to 1,6-HAT Processes with Masked Amine Substrates5 Conclusions and Outlook

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Section: Synpacts Syn Lettmentioning

confidence: 81%

Modifying Positional Selectivity in C–H Functionalization Reactions with Nitrogen-Centered Radicals: Generalizable Approaches to 1,6-Hydrogen-Atom Transfer Processes

Short¹,

Blackburn²,

Roizen³

2019

Synlett

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“…The first 1,5-HAT reaction, the classic Hoffmann-Löffler-Freytag reaction, originated in 1883 and involves photolysis of a protonated N-chloroamine after which the resulting aminium radical abstracts a hydrogen from a carbon five atoms away, resulting in δ-chlorination. The 1,5-radical translocation is thermodynamically favourable because the abstraction of the hydridic hydrogen atom is exergonic and occurs through a sixmembered transition state, although 1,6-and 1,7-translocations involving sulfamates and sulfamides have also been reported by the group of Roizen [218,219]. Following the translocation of the halide, an intramolecular nucleophilic substitution reaction then furnishes pyrrolidine products.…”

Section: − N Bond Formationmentioning

confidence: 99%

Pushing the boundaries of C–H bond functionalization chemistry using flow technology

2020

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C-H functionalization chemistry is one of the most vibrant research areas within synthetic organic chemistry. While most researchers focus on the development of small-scale batch-type transformations, more recently such transformations have been carried out in flow reactors to explore new chemical space, to boost reactivity or to enable scalability of this important reaction class. Herein, an up-to-date overview of C-H bond functionalization reactions carried out in continuous-flow microreactors is presented. A comprehensive overview of reactions which establish the formal conversion of a C-H bond into carbon-carbon or carbonheteroatom bonds is provided; this includes metal-assisted C-H bond cleavages, hydrogen atom transfer reactions and C-H bond functionalizations which involve an S E-type process to aromatic or olefinic systems. Particular focus is devoted to showcase the advantages of flow processing to enhance C-H bond functionalization chemistry. Consequently, it is our hope that this review will serve as a guide to inspire researchers to push the boundaries of C-H functionalization chemistry using flow technology.

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“…While when the additive was altered to nBu4NBr, the bromination product of leucine derivative could be achieved in 71% yield (Scheme 61b). In 2020, Roizen's group installed a N-chlorosulfamide group to the valine derivative (Scheme 62) [137]. The substrate could proceed with chlorine-atom abstraction, 1,6-HAT, and the final chlorination process to finish the formal 1,6-chlorine-atom transfer reaction.…”

Section: C-h Chlorination and Brominationmentioning

confidence: 99%

“…Phosphorus-containing organic compounds occupy an important place in pharmaceuticals [118], catalysts [119] and materials [120], resulting in the great demand of methods for the introduction of In 2020, Roizen's group installed a N-chlorosulfamide group to the valine derivative (Scheme 62) [137]. The substrate could proceed with chlorine-atom abstraction, 1,6-HAT, and the final chlorination process to finish the formal 1,6-chlorine-atom transfer reaction.…”

Section: C-p Formationmentioning

confidence: 99%

Recent Advances in Rapid Synthesis of Non-proteinogenic Amino Acids from Proteinogenic Amino Acids Derivatives via Direct Photo-Mediated C–H Functionalization

Yuan

Liu

et al. 2020

Molecules

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Non-proteinogenic amino acids have attracted tremendous interest for their essential applications in the realm of biology and chemistry. Recently, rising C–H functionalization has been considered an alternative powerful method for the direct synthesis of non-proteinogenic amino acids. Meanwhile, photochemistry has become popular for its predominant advantages of mild conditions and conservation of energy. Therefore, C–H functionalization and photochemistry have been merged to synthesize diverse non-proteinogenic amino acids in a mild and environmentally friendly way. In this review, the recent developments in the photo-mediated C–H functionalization of proteinogenic amino acids derivatives for the rapid synthesis of versatile non-proteinogenic amino acids are presented. Moreover, postulated mechanisms are also described wherever needed.

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Sulfamides direct radical-mediated chlorination of aliphatic C–H bonds

Abstract: Amine-anchored sulfamides direct radical-mediated chlorination of aliphatic C–H bonds. The site of C–H abstraction can be modulated by varying the sulfamide nitrogen substituents, a feature that has not been demonstrated with other substrate classes.

Cited by 36 publications

References 64 publications

Modifying Positional Selectivity in C–H Functionalization Reactions with Nitrogen-Centered Radicals: Generalizable Approaches to 1,6-Hydrogen-Atom Transfer Processes

Modifying Positional Selectivity in C–H Functionalization Reactions with Nitrogen-Centered Radicals: Generalizable Approaches to 1,6-Hydrogen-Atom Transfer Processes

Pushing the boundaries of C–H bond functionalization chemistry using flow technology

Recent Advances in Rapid Synthesis of Non-proteinogenic Amino Acids from Proteinogenic Amino Acids Derivatives via Direct Photo-Mediated C–H Functionalization

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