Feedback Inhibition in Chemical Catalysis Leads the Dynamic Kinetic to Kinetic Resolution in C3-Indolylation of Spiro-epoxyoxindoles

Hajra, Saumen; Roy, Sayan

doi:10.1021/acs.orglett.0c00028

Cited by 23 publications

(22 citation statements)

References 29 publications

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“…It is further envisioned that the presence of oxindole unit in spirooxazolidinone similarly will enable the release of CO 2 under acidic conditions as shown in Fig. 1 ) 53 , 54 . More importantly, the spirooxazolidinoyl oxindole is a potential drug candidate 47 – 49 , so this CO 2 fixation could be excellent and cheap method for its production.…”

Section: Resultsmentioning

confidence: 99%

Efficient chemical fixation and defixation cycle of carbon dioxide under ambient conditions

Hajra

Biswas

2020

Sci Rep

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Chemical fixation of CO2 as a C1 feedstock for producing value-added products is an important post-combustion technology reducing the CO2 emission. As it is an irreversible process, not considered for the CO2 capture and release. Overall, these chemical transformations also do not help to mitigate global warming, as the energy consumed in different forms is much higher than the amount of CO2 fixed by chemical reactions. Here we describe the development of re-generable chemical fixation of CO2 by spiroaziridine oxindole, where CO2 is captured (chemical fixation) under catalyst-free condition at room temperature both in aqueous and non-aqueous medium even directly from the slow stream of flue gas producing regioselectively spirooxazolidinyl oxindoles, a potential drug. The CO2-adduct is reversed back to the spiroaziridine releasing CO2 under mild conditions. Further both the fixation-defixation of CO2 can be repeated under near ambient conditions for several cycles in a single loop using a recyclable reagent.

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Section: Resultsmentioning

confidence: 99%

Efficient chemical fixation and defixation cycle of carbon dioxide under ambient conditions

Hajra

Biswas

2020

Sci Rep

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“…Similar to our earlier work, [9] when we attempted the DKR condition on the N-Bn spiro-epoxide (�)-1 with the cat. E at rt, it could not reveal a similar result.…”

Section: Kinetic Resolution Of Spiro-epoxidesmentioning

confidence: 69%

“…We opened up the evaluation with N-benzyl, N-allyl, and N-methyl protected spiro-epoxides (�)-1a-1c along with a diverse array of Scheme 3. Catalytic enantioselective C3-indolylation of NHspiroepoxide (�)-1 [9] .…”

Section: Substrate Scope Of the Catalytic Enantioselective C-3 Indolymentioning

confidence: 99%

“…E (Z = SbF 6 ) introduced the dynamic kinetic version (DKR) in absence of water (Scheme 3). [9] This recent portrayal of chiral Co(III)-salen catalyzed asymmetric ring-opening reaction of N-free spiro-epoxyoxindoles encouraged us to study the catalytic…”

Section: Introductionmentioning

confidence: 99%

“…E (Z=SbF 6 ) introduced the dynamic kinetic version (DKR) in absence of water (Scheme 3). [9] This recent portrayal of chiral Co(III)‐salen catalyzed asymmetric ring‐opening reaction of N ‐free spiro‐epoxyoxindoles encouraged us to study the catalytic enantioselective ring‐opening reaction to a large number of N ‐protected spiro‐epoxides in detail and to investigate the plausible mechanism. Here we exhibit the efficiency of this method over the previously established Brønsted acid condition as well.…”

Section: Introductionmentioning

confidence: 99%

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Co(III)salen Catalyzed Enantioselective C3‐Indolylation of Spiro‐Epoxyoxindoles and Its Mechanistic Studies

2020

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Catalytic asymmetric C3-indolylation of N-protected spiro-epoxyoxindoles has been developed for the access of 3-(3-indolyl)-oxindole methanols with excellent enantioselectivity (ee up to > 99%). The widespread substrate scope and easily accessible Co(III)-salen over 1,1'-Spirobiindane-7,7'-diol phosphoric acid prove our condition to be more beneficial than the chiral Brønsted acid-catalyzed reaction. Further, kinetic resolution of spiro-epoxides is achieved in high enantiomeric excess under certain conditions. The detailed mechanistic study endorses that the feedback inhibition played a key role which restricts the dynamic kinetic resolution process. Besides it also revealed the S N 2' mechanism for the Co(III)-salen catalysed C3-indolylation of spiro-epoxyoxindoles.

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Regioselective Hydroperoxylation of Aziridines and Epoxides Only with Aqueous Hydrogen Peroxide

2021

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A catalyst and organic solvent-free regioselective hydroperoxylation of aziridines and epoxides, including spiroaziridine-and spiroepoxy oxindoles have been explored with commercially available 50% aq. H 2 O 2 . This method provides an access to secondary benzylic β-hydroperoxy amines and -alcohols and tertiary 3-hydroperoxy oxindoles. The protocol is also applicable to the less reactive alkyl aziridines. Furthermore, an acid-catalyzed Kornblum-DeLaMare type rearrangement of secondary benzylic hydroperoxide has also been revealed to afford amino-and hydroxyl ketones.

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Feedback Inhibition in Chemical Catalysis Leads the Dynamic Kinetic to Kinetic Resolution in C3-Indolylation of Spiro-epoxyoxindoles

Cited by 23 publications

References 29 publications

Efficient chemical fixation and defixation cycle of carbon dioxide under ambient conditions

Efficient chemical fixation and defixation cycle of carbon dioxide under ambient conditions

Co(III)salen Catalyzed Enantioselective C3‐Indolylation of Spiro‐Epoxyoxindoles and Its Mechanistic Studies

Regioselective Hydroperoxylation of Aziridines and Epoxides Only with Aqueous Hydrogen Peroxide

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