Selectivity in Ring‐Closing Metathesis: Synthesis of Propellanes and Angular Aza‐tricycles

Kotha, Sambasivarao; Aswar, Vikas R.; Ansari, Saima

doi:10.1002/adsc.201801123

Cited by 18 publications

(5 citation statements)

References 65 publications

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“…Later, RCM [37] of vinyl ethers 40-43 using the first-generation Grubbs catalyst 15 (5-20 mol%) furnished TPM containing benzofurans 44-47 in 89-93 % yields (Scheme 3). To achieve better insight, we recorded single-crystal X-ray data of compound 47.…”

Section: Chemistryselectmentioning

confidence: 99%

Diversity Oriented Approach to New Tetrahedral Building Blocks by Ring‐Closing Metathesis

Kotha

Solanke

2023

ChemistrySelect

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We disclose an approach to a library of novel multidimensional O‐heterocycles based on a rigid, tetrahedral core. New derivatives of tetraphenylmethane (TPM) have been synthesized by employing Claisen rearrangement (CR) and ring‐closing metathesis (RCM) as key steps. Mono‐, di‐, tri‐, and tetra‐substituted benzofurans, 2H‐chromenes, and benzoxepine derivatives are reported. Various heterocyclic cores present in these compounds are key structural elements present in several natural products and pharmaceuticals as well as valuable precursors for the construction of complex molecules with the tetrahedral framework. To the best of our knowledge, this is the first report involving the synthesis of five‐, six‐, and seven‐membered O‐heterocycles in TPM core and the basecatalyzed inexpensive synthesis of several isomerized intermediates that are useful to prepare oxacycles such as benzofuran and 2H‐chromenes. The symmetrical and unsymmetrical one, two, three, and four‐armed architecture of TPM makes it a valuable starting point for building complex molecular and supramolecular architectures. To expand the unmet chemical space of the TPM core, we have prepared twenty new derivatives by a unified approach. Additionally, we report a simple, catalyst‐free, and inexpensive recipe for double bond isomerization based on KOtBu to assemble various oxacycles derived from different trityl chloride derivatives.

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Section: Chemistryselectmentioning

confidence: 99%

Diversity Oriented Approach to New Tetrahedral Building Blocks by Ring‐Closing Metathesis

Kotha

Solanke

2023

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“…When N-allylcarbazole 237 was treated with catalyst G-I, the propellane 238 was selectively obtained as the major product and angular aza-tricyclic compound 239 was the minor product (Scheme 50). 67 Scheme 50 Different outcomes of RCM…”

Section: Examples Of Miscellaneous Selectivitymentioning

confidence: 99%

Selectivity: A Goal for Synthetic Economy

Kotha¹,

Ansari²,

Gupta³

2022

Synlett

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Chemical reactivity plays a major role in understanding several aspects of selectivity. Therefore, we present a plethora of reactions that demonstrate our efforts in exploiting interesting cases of selectivity observed in the past three decades. Among them, chemoselectivity, regioselectivity and steroselectivity are discussed. Strain, steric factors, and separations of the reacting functionalities are displayed as prominent features in generating selectivity.

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“…Inspiring form this simple yet powerful procedure and also from the applications of the indole moiety containing molecules, two years later to this report, in 2014, Kotha and his teammates have successfully employed this strategy for the synthesis of C 2 -and C s -symmetric bis-indole Low Melting Mixture of L-(+)-Tartaric Acid and N,N′-Dimethyl Urea: A New Arrival... DOI: http://dx.doi.org/10.5772/intechopen.97392 systems (52, 53, 58, 60-62) from bicyclo-3,7-diones and 1-methyl-1-phenylhydrazine under DMU/TA (7:3) reaction conditions (Figure 5) [29]. Later on, Kotha's team nicely expanded this delightful method for the generation of a variety of carbazole derivatives (32)(33)(34)(35) including pyrano-carbazole (36) and aza-cyclophane based carbazoles (37 and 38) as depicted Figure 4 [30][31][32] in Figure 4. Interestingly, utilizing this tactic, they have also prepared carbazole-based natural products such as tijapinazole D (32) and tijapinazole I (33) in addition to the crown-based indolocarbazole (47).…”

Section: Construction Of Indole Systems Under a Low Melting Mixture Of Dmu/tamentioning

confidence: 99%

“…Interestingly, utilizing this tactic, they have also prepared carbazole-based natural products such as tijapinazole D (32) and tijapinazole I (33) in addition to the crown-based indolocarbazole (47). Moreover, in the laboratory of Kotha's group, diverse heteropolycyclic compounds (39)(40)(41)(42)(43) in addition to the propellane derivatives (44) have been assembled by using ring-closing metathesis (RCM) and Fischer indolization in a low melting mixture of DMU/TA as crucial steps, (Figure 4) [33][34][35]. Keeping the importance of C 3 -symmetric molecules in medicinal and bioorganic chemistry besides their vital role in material science and technology, the same group has also prepared star-shaped C 3 -symmetric compounds 45 and 46 involving cyclotrimerization and DMU/TA mediated indolization approach (Figure 4) [36].…”

Section: Construction Of Indole Systems Under a Low Melting Mixture Of Dmu/tamentioning

confidence: 99%

Low Melting Mixture of L-(+)-Tartaric Acid and N,N′-Dimethyl Urea: A New Arrival in the Green Organic Synthesis

Ali¹

2021

Current Topics in Chirality - From Chemistry to Biology

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After the first report of deep eutectic mixtures by the team of Abbott in 2003, the advent of green synthesis has been progressively changing the way synthetic chemistry is thought and also taught. Since then, a plethora of efforts worldwide have been taken to stretch the ideas of sustainable as well as environmentally benign approaches to do the crucial synthetic organic transformations under operationally simple yet effective conditions. Although, till date, several green synthetic strategies for examples ultrasound, microwaves, flow as well as grindstone chemistry etc., and green reaction media (e.g. ionic liquid, water, scCO2, and so forth) have successfully been invented. But a low melting mixture of L-(+)-tartaric acid (TA) and N,N′-dimethylurea (DMU), usually plays a double and/or triple role (solvent, catalyst, and/or reagent), though still infancy but enjoys several eye-catching properties like biodegradability, recyclability, non-toxicity, good thermal stability, tunable physiochemical properties, low vapor pressure as well as reasonable prices in addition to the easy preparation with wide functional groups tolerance. To this context, keeping the importance of this novel low melting mixture in mind, we intended to reveal the advancements taken place in this wonderful area of research since its first report by the Köenig’s group in 2011 to till date. In this particular chapter, firstly we would disclose the importance of the green synthesis followed by a brief description of deep-eutectic solvents (DESs) particularly emphasizing on the role of L-(+)-TA and DMU from modern synthetic chemistry perspective.

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Selectivity in Ring‐Closing Metathesis: Synthesis of Propellanes and Angular Aza‐tricycles

Cited by 18 publications

References 65 publications

Diversity Oriented Approach to New Tetrahedral Building Blocks by Ring‐Closing Metathesis

Diversity Oriented Approach to New Tetrahedral Building Blocks by Ring‐Closing Metathesis

Selectivity: A Goal for Synthetic Economy

Low Melting Mixture of L-(+)-Tartaric Acid and N,N′-Dimethyl Urea: A New Arrival in the Green Organic Synthesis

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