Mechanistic Insights on Iodine(III) Promoted Metal-Free Dual C–H Activation Involved in the Formation of a Spirocyclic Bis-oxindole

Sreenithya, A.; Sunoj, Raghavan B.

doi:10.1021/ol503161g

Cited by 36 publications

(21 citation statements)

References 46 publications

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“…This functional group displays ahigh degree of chemoselectivity,a sd emonstrated, for example, by an octapeptide derived from Sandostatin, [18,19] or by co-enzymeA. [21][22][23][24][25][26][27][28][29][30] We previously investigatedt he electronica nd structural properties leadingt o the distinct reactivity of reagent 1 as well as polar mechanistic details in combination with N-a nd S-nucleophiles. [21][22][23][24][25][26][27][28][29][30] We previously investigatedt he electronica nd structural properties leadingt o the distinct reactivity of reagent 1 as well as polar mechanistic details in combination with N-a nd S-nucleophiles.…”

Section: Introductionmentioning

confidence: 99%

“…[20] Although the chemistry of iodanes is well established,o nly recent computational studies revealed the mechanistic versatility of l 3 -iodanes, reminiscent of that of transition metals. [21][22][23][24][25][26][27][28][29][30] We previously investigatedt he electronica nd structural properties leadingt o the distinct reactivity of reagent 1 as well as polar mechanistic details in combination with N-a nd S-nucleophiles. [24,25,30] Thus, the activation of reagent 1 by protonation is essential.…”

Section: Introductionmentioning

confidence: 99%

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S‐Trifluoromethylation of Thiols by Hypervalent Iodine Reagents: A Joint Experimental and Computational Study

Sala

Santschi

Jungen

et al. 2016

Chemistry A European J

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The radical trifluoromethylation of thiophenol in condensed phase applying reagent 1 (3,3-dimethyl-1-(trifluoromethyl)-1λ(3),2-benziodoxol) has been examined by both theoretical and experimental methodologies. On the basis of ab initio molecular dynamics and metadynamics we show that radical reaction mechanisms favourably compete with polar ones involving the S-centred nucleophile thiophenol, their free energies of activation, ΔF(≠), lying between 9 and 15 kcal mol(-1). We further show that the origin of the proton activating the reagent is important. Hammett plot analysis reveals intramolecular protonation of 1, thus generating negative charge on the sulfur atom in the rate-determining step. The formation of a CF3 radical can be thermally induced by internal dissociative electron transfer, its activation energy, ΔF(≠), amounting to as little as 10.8 and 2.8 kcal mol(-1) for reagent 1 and its protonated form 2, respectively. The reduction of the iodine atom by thiophenol occurs either subsequently or in a concerted fashion.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

S‐Trifluoromethylation of Thiols by Hypervalent Iodine Reagents: A Joint Experimental and Computational Study

Sala

Santschi

Jungen

et al. 2016

Chemistry A European J

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“…Furthermore, Sunoj and Sreenithya [ 92 ] developed a metal-free approach for the synthesis of 1,1'-dimethyl-3,3'-spirobi[indoline]-2,2'-dione ( 61 ) from N 1 , N 3 -dimethyl- N 1 , N 3 -diphenylmalonamide ( 60 ) using PIFA ( 31 ) in trifluoroethanol at room temperature. The spirolactam 61 was isolated in 75% yield ( Scheme 21 ).…”

Section: Reviewmentioning

confidence: 99%

Synthesis of spirocyclic scaffolds using hypervalent iodine reagents

Singh¹,

Kole²,

Mangaonkar³

et al. 2018

Beilstein J. Org. Chem.

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Hypervalent iodine reagents have been developed as highly valuable reagents in synthetic organic chemistry during the past few decades. These reagents have been identified as key replacements of various toxic heavy metals in organic synthesis. Various synthetically and biologically important scaffolds have been developed using hypervalent iodine reagents either in stoichiometric or catalytic amounts. In addition, hypervalent iodine reagents have been employed for the synthesis of spirocyclic scaffolds via dearomatization processes. In this review, various approaches for the synthesis of spirocyclic scaffolds using hypervalent iodine reagents are covered including their stereoselective synthesis. Additionally, the applications of these reagents in natural product synthesis are also covered.

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“…In a recent report, Sreenithya and Sunoj reported a detailed mechanistic study of phenyliodonium bis‐trifluoroacetate (PIFA) promoted dual CH functionalization of an anilide derivative to form spiro bis‐oxindole framework (Scheme (a)) using DFT computations at the SMD (TFE) /M06‐2X/LANL2DZ(I),6‐31G** level of theory to shed light on the key intermediates and TSs involved . Reaction starts with initial substrate coordination to iodine(III) center through ligand exchange ( TS ( 1 a –2 a )) followed by a proton abstraction by trifluroacetate ( TS ( 2 a –3 a )) to form an iodoenolate 3 a .…”

Section: Ch Functionalizationmentioning

confidence: 99%

Hypercoordinate iodine(III) promoted reactions and catalysis: an update on current mechanistic understanding

Sreenithya

Surya

Sunoj

2017

WIREs Comput Mol Sci

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Mild and environment friendly hypercoordinate iodine compounds exhibit promising reactivities resembling that of transition metal catalysts. Hypercoordinate iodine reagents or catalysts are increasingly been employed in contemporary organic synthesis. However, mechanistic insights on such reactions continue to remain rather limited. Recent advances in the mechanistic understanding on a selected set of reactions involving hypercoordinate iodine form the main theme of this review. An overview of bonding, reactivity, and mechanistic insights on iodine(III) reactions such as α-functionalization of carbonyl compounds, alkynylation, amination, C H functionalization, phenol dearomatization, and trifluoromethylation have been described. In keeping with the current practices in mechanistic studies, we have maintained an interdisciplinary flavor in this compilation by providing a balanced view of computational and experimental understanding on the burgeoning domain of hypercoordinate iodine mediated reactions and catalysis. FIGURE 1 | Molecular orbital (MO) diagram for three-center-fourelectron (3c-4e) bond in hypercoordinate iodine compound RIL 2 . SCHEME 1 (a) General representation of α-tosyloxylation ketone catalyzed by Koser's reagent. (b) General mechanism for the α-tosyloxylation ketone. (c) Commonly employed iodoarenes in α-tosyloxylation. Overview wires.wiley.com/compmolsci SCHEME 2 (a) Effect of different substituents on the catalytic activity of iodoaryl in α-tosyloxylation. (b) Effect of different substituents on dihedral angle θ(C1-C2-I3-O4). (c) Formation of iodono intermediate 4 and the related ΔG rxn . WIREs Computational Molecular Science Hypercoordinate iodine(III) promoted reactions and catalysis Volume 7,

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Mechanistic Insights on Iodine(III) Promoted Metal-Free Dual C–H Activation Involved in the Formation of a Spirocyclic Bis-oxindole

Cited by 36 publications

References 46 publications

S‐Trifluoromethylation of Thiols by Hypervalent Iodine Reagents: A Joint Experimental and Computational Study

S‐Trifluoromethylation of Thiols by Hypervalent Iodine Reagents: A Joint Experimental and Computational Study

Synthesis of spirocyclic scaffolds using hypervalent iodine reagents

Hypercoordinate iodine(III) promoted reactions and catalysis: an update on current mechanistic understanding

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