Kinetic Study of the Radical Azidation with Sulfonyl Azides

Weidner, Karin; Renaud, Philippe

doi:10.1071/ch12523

Cited by 11 publications

(9 citation statements)

References 20 publications

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“…The reactive azide 10 can be readily prepared in situ and was successfully used by Renaud and us for radical azidation reactions before. [24][25][26] Under the above optimized conditions developed for the alkynylation process, the desired reaction proceeded smoothly to afford the rather unstable tertiary azide 11 in 70% isolated yield ( Figure 6). To further document the potential of the 1,3-alkene difunctionalization strategy, we investigated the photoredox-catalyzed three-component reaction of allylboronic ester 1a with various Michael acceptors as C-radical trapping reagents and the Langlois reagent (CF 3 SO 2 Na) as the trifluoromethyl radical source.…”

Section: Resultsmentioning

confidence: 99%

Radical 1,3-Difunctionalization of Allylboronic Esters with Concomitant 1,2-Boron Shift

Jana

Bhunia

Studer

2020

Chem

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Radical 1,3-trifluoromethylation/alkynylation of various allylboronic esters with concomitant 1,2-boron shift with alkynyl triflones is reported. These chain reactions proceed via CF 3-radical addition to the allylic double bond, and the adduct radical undergoes 1,2-boron migration to give a translocated C-radical that is trapped by the alkynyl triflone. As products, 1,2,3-trisubstituted alkanes with the trifluoromethyl group at position 1 and the alkynyl functionality at position 3 are formed. The valuable boron moiety is retained in the product and is rearranged to position 2. By using trifluoromethanesulfonyl azide as the radical trapping reagent, the cascade provides a 1-trifluoromethyl-3-azidyl-alk-2-ylboronic ester as the product and Michael acceptors as trapping reagents in combination with the Langlois reagent as the CF 3-radical precursor applying photoredox catalysis afford the corresponding 3-alkylated congeners in a three-component process. Further, the stereochemical course of the 1,2-boron migration and the trapping reaction are investigated.

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Section: Resultsmentioning

confidence: 99%

Radical 1,3-Difunctionalization of Allylboronic Esters with Concomitant 1,2-Boron Shift

Jana

Bhunia

Studer

2020

Chem

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“…To document the diversity of our approach, related radical transformations varying the sulfone‐type radical trapping reagent were studied and the azidation was first explored (Scheme ). Reaction of 1 h with trifluoromethanesulfonylazide (TfN 3 , 4 a ) under the above optimized conditions afforded the azide 5 a in 48 % yield. With DLP as the initiator, the yield could be increased to 76 % and all following azidations were initiated with DLP.…”

Section: Methodsmentioning

confidence: 99%

Diversity‐Oriented Desulfonylative Functionalization of Alkyl Allyl Sulfones

Xia

Studer

2019

Angewandte Chemie

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The diversity-oriented desulfonylative functionalization of alkylallyl sulfones with various sulfone-type reagents by radical chemistry has been developed. The readily installed allylsulfonyl moiety acts as aC -radical precursor,w hich is substituted by various functionalities using sulfur-based radical trapping reagents.T he generality of this approach is documented by the successful desulfonylative alkynylation, azidation, trifluoromethylthiolation, sulfenylation, trifluoromethylselenylation, halogenation, and deuteration. The method is compatible with aw ide range of functional groups.C onsidering the deuteration, products are obtained in good yields with ahigh level of deuterium incorporation. Scheme 1. Diversity-oriented transformation by radical reactions.

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“…Notably, whereas the reactivity of a b-trifluoromethylalkyl radical is meanwhile very well established, [12] atrifluoromethylalkyl radicals are not intensively investigated, since they are more difficult to generate. Along these lines, we failed running the cascade with CF 3 SO 2 Cl, CF 3 SO 2 N 3 [13] and CF 3 SO 2 CH=CHPh. [14] In summary, we have presented a practical method for the 1,1,2-trifunctionalization of terminal alkynes using radical chemistry.…”

Section: Angewandte Chemiementioning

confidence: 99%

1,1,2‐Trifunctionalization of Terminal Alkynes by Radical Addition–Translocation–Cyclization–Trapping for the Construction of Highly Substituted Cyclopentanes

2020

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Radical 1,1,2-trifunctionalization of terminal alkynes by an addition-translocation-cyclization-trapping sequence using readily available alkynyl triflones as trifluoromethyl radical precursors and trapping reagents is reported. Cascades occur by addition of the trifluoromethyl radical to a terminal alkyne, 1,5-hydrogen atom transfer, 5-exo-cyclization, and subsequent alkynylation to provide (1-trifluoromethyl)propargyl cyclopentanes. Reactions proceed with commercial dibenzoyl peroxide or a,a'-azobisisobutyronitrile as the initiator at elevated temperature and provide the highly substituted cyclopentanes in good yields.

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Kinetic Study of the Radical Azidation with Sulfonyl Azides

Cited by 11 publications

References 20 publications

Radical 1,3-Difunctionalization of Allylboronic Esters with Concomitant 1,2-Boron Shift

Radical 1,3-Difunctionalization of Allylboronic Esters with Concomitant 1,2-Boron Shift

Diversity‐Oriented Desulfonylative Functionalization of Alkyl Allyl Sulfones

1,1,2‐Trifunctionalization of Terminal Alkynes by Radical Addition–Translocation–Cyclization–Trapping for the Construction of Highly Substituted Cyclopentanes

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