An Untethered and Formal Intermolecular Hexadehydro-Diels-Alder Reaction: Alkynylboronates with 2-(1,3-Butadiynyl)pyridines Trinadh Kaicharla, Mengyuan Jin, Thomas R. Hoye Journal of the American Chemical Society, 2024 We show that 2-diynylpyridine and a Bpin-terminated monoyne or diyne will cross-react to form benzyne intermediates. These reactive intermediates are captured by various in situ trapping agents to give products of three-component reactions. Various control reactions, substrate modification, binding studies, and DFT analysis suggest that a small amount of a noncovalent Lewis acid-base complex is the active species within which the diyne and diynophile engage to produce the benzyne. Only a single isomeric benzyne is formed when a Bpin-diyne is used; this selectivity is rationalized by the geometric distortion seen in the DFT-computed diradical intermediate.
Novel conversions of a multifunctional, bio-sourced lactone carboxylic acid Trinadh Kaicharla, Sangjun Lee, Ruiqin Wang, Ashok D. Pehere, Shu Xu, Thomas R. Hoye Arkivoc, 2024 The plant-derived compounds furfuryl alcohol and itaconic anhydride are known to undergo a Diels-Alder reaction at room temperature and in bulk to efficiently give an alkene-containing lactone carboxylic acid. Reported here is the conversion of this substance to a variety of derivatives via hydrogenation, epoxidation, or halolactonization reactions. Most notable is the formation of a set of three related acrylate or methacrylate esters (see graphical abstract) produced by direct acylative ring opening of ether bonds using Sc(OTf) 3 and (meth)acrylic anhydride. These esters are viewed as promising candidates for use as biorenewable monomers in reversible addition-fragmentation chain transfer (RAFT) polymerization reactions.
Examples Showing the Utility of Doping Experiments in 1H NMR Analysis of Mixtures Trinadh Kaicharla, Bhavani Shankar Chinta, Thomas R. Hoye Journal of Organic Chemistry, 2022 Here we provide examples that demonstrate the value of using properly designed and easily performed doping experiments to give insights about the nature of the analyte(s) present in a 1H NMR sample. Two mixtures, the first quite complex and the second far less so, have been chosen: (i) the crude pyrolysate from reaction of butyric acid in (supercritical) water at 600 °C and (ii) a mixture of two basic amines. In the former, 13 distinct carbonyl-containing compounds, ranging in relative concentration of nearly 2 orders of magnitude, were positively identified. The latter highlights the advantage of using a doping experiment as opposed to merely comparing the spectra from two separate samples containing the same analyte.
A Bifunctional Copper Catalyst Enables Ester Reduction with H2: Expanding the Reactivity Space of Nucleophilic Copper Hydrides Birte M. Zimmermann, Trung Tran Ngoc, Dimitrios-Ioannis Tzaras, Trinadh Kaicharla, Johannes F. Teichert Journal of the American Chemical Society, 2021 Employing a bifunctional catalyst based on a copper(I)/NHC complex and a guanidine organocatalyst, catalytic ester reductions to alcohols with H2 as terminal reducing agent are facilitated. The approach taken here enables the simultaneous activation of esters through hydrogen bonding and formation of nucleophilic copper(I) hydrides from H2, resulting in a catalytic hydride transfer to esters. The reduction step is further facilitated by a proton shuttle mediated by the guanidinium subunit. This bifunctional approach to ester reductions for the first time shifts the reactivity of generally considered "soft" copper(I) hydrides to previously unreactive "hard" ester electrophiles and paves the way for a replacement of stoichiometric reducing agents by a catalyst and H2.
Stereoselective Alkyne Hydrohalogenation by Trapping of Transfer Hydrogenation Intermediates Manas Das, Trinadh Kaicharla, Johannes F. Teichert Organic Letters, 2018 A catalytically generated vinylcopper complex, the reactive intermediate of a copper(I)-catalyzed alkyne transfer hydrogenation, can be trapped by commercially available halogen electrophiles. In this manner, internal alkynes can stereoselectively be hydrohalogenated to the corresponding vinyl chlorides, bromides, and iodides.
Metal-Free, Brønsted Acid-Catalyzed Formal [3+2] Annulation of Quinone Monoacetals with 2-Naphthols Anu Jacob, Tony Roy, Trinadh Kaicharla, Akkattu T. Biju Journal of Organic Chemistry, 2017 An operationally simple and metal-free cross-coupling of quinone monoacetals (QMAs) with 2-naphthols catalyzed by triflic acid is reported. This formal [3+2] annulation allowed the synthesis of diverse naphtho[2,1-b]benzofuran derivatives in moderate to good yields. Preliminary mechanistic studies reveal the initial nucleophilic substitution of QMAs with 2-naphthols in preference to the mixed acetal formation and subsequent [3,3] sigmatropic rearrangement.
AgOTf-catalyzed dehydrative [3+2] annulation of aziridines with 2-naphthols Trinadh Kaicharla, Anu Jacob, Rajesh G. Gonnade, Akkattu T. Biju Chemical Communications, 2017 The reaction of 2-naphthols with aziridines in the presence of AgOTf proceeding in a dehydrative, [3+2] annulation leading to benzoindolines is reported.
The Aryne [2,3] Stevens Rearrangement Tony Roy, Manikandan Thangaraj, Trinadh Kaicharla, Rupa V. Kamath, Rajesh G. Gonnade, Akkattu T. Biju Organic Letters, 2016
An untethered and formal intermolecular hexadehydro-Diels–Alder reaction: Alkynylboronates with 2-(1, 3-Butadiynyl) pyridines T Kaicharla, M Jin, TR Hoye Journal of the American Chemical Society 146 (50), 34510-34516 , 2024 2024 Citations: 4
Novel conversions of a multifunctional, bio-sourced lactone carboxylic acid T Kaicharla, S Lee, R Wang, AD Pehere, S Xu, TR Hoye ARKIVOC: free online journal of organic chemistry 2, 202312081 , 2023 2023
Examples Showing the Utility of Doping Experiments in 1 H NMR Analysis of Mixtures T Kaicharla, BS Chinta, TR Hoye The Journal of organic chemistry 87 (9), 5660-5667 , 2022 2022 Citations: 4
A Bifunctional Copper Catalyst Enables Ester Reduction with H 2 : Expanding the Reactivity Space of Nucleophilic Copper Hydrides BM Zimmermann, TT Ngoc, DI Tzaras, T Kaicharla, JF Teichert Journal of the American Chemical Society 143 (40), 16865-16873 , 2021 2021 Citations: 48
Correction: β-Methyl-δ-valerolactone-containing thermoplastic poly (ester-amide) s: synthesis, mechanical properties, and degradation behavior DM Guptill, BS Chinta, T Kaicharla, S Xu, TR Hoye Polymer Chemistry 12 (21), 3210-3210 , 2021 2021
Using alcohols as simple H 2-equivalents for copper-catalysed transfer semihydrogenations of alkynes T Kaicharla, BM Zimmermann, M Oestreich, JF Teichert Chemical Communications 55 (89), 13410-13413 , 2019 2019 Citations: 42
Stereoselective alkyne hydrohalogenation by trapping of transfer hydrogenation intermediates M Das, T Kaicharla, JF Teichert Organic Letters 20 (16), 4926-4929 , 2018 2018 Citations: 53
Benzoxaphosphole compounds and a process for preparation thereof AT Biju, A Bhunia, T Kaicharla US Patent 9,902,746 , 2018 2018
Metal-free, Brønsted acid-catalyzed formal [3+ 2] annulation of quinone monoacetals with 2-naphthols A Jacob, T Roy, T Kaicharla, AT Biju The Journal of Organic Chemistry 82 (20), 11269-11274 , 2017 2017 Citations: 26
Oxindole compounds, solvent-free synthesis and use thereof AT Biju, T Kaicharla, SR Yetra, T Roy US Patent 9,783,496 , 2017 2017
Transition-metal-free N-arylation of tertiary amines using arynes AT Biju, SS Bhojgude, T Kaicharla US Patent 9,650,329 , 2017 2017
AgOTf-catalyzed dehydrative [3+ 2] annulation of aziridines with 2-naphthols T Kaicharla, A Jacob, RG Gonnade, AT Biju Chemical Communications 53 (58), 8219-8222 , 2017 2017 Citations: 31
The aryne [2, 3] Stevens rearrangement T Roy, M Thangaraj, T Kaicharla, RV Kamath, RG Gonnade, AT Biju Organic letters 18 (20), 5428-5431 , 2016 2016 Citations: 58
Lewis acid catalyzed selective reactions of donor–acceptor cyclopropanes with 2‐naphthols T Kaicharla, T Roy, M Thangaraj, RG Gonnade, AT Biju Angewandte Chemie 128 (34), 10215-10218 , 2016 2016 Citations: 139
Employing carboxylic acids in aryne multicomponent coupling triggered by aziridines/azetidines T Roy, SS Bhojgude, T Kaicharla, M Thangaraj, B Garai, AT Biju Organic Chemistry Frontiers 3 (1), 71-76 , 2016 2016 Citations: 42
Transition-metal-free synthesis of benzo-fused five-and six-membered heterocycles employing arynes T Kaicharla, AT Biju Green Synthetic Approaches for Biologically Relevant Heterocycles, 45-76 , 2015 2015 Citations: 6
Practical Synthesis of Phthalimides and Benzamides by a Multicomponent Reaction Involving Arynes, Isocyanides, and CO 2 /H 2 O T Kaicharla, M Thangaraj, AT Biju Organic letters 16 (6), 1728-1731 , 2014 2014 Citations: 93
Multicomponent reactions involving phosphines, arynes and aldehydes A Bhunia, T Kaicharla, D Porwal, RG Gonnade, AT Biju Chemical Communications 50 (77), 11389-11392 , 2014 2014 Citations: 64
Employing arynes in transition-metal-free monoarylation of aromatic tertiary amines SS Bhojgude, T Kaicharla, AT Biju Organic letters 15 (21), 5452-5455 , 2013 2013 Citations: 102
MOST CITED SCHOLAR PUBLICATIONS
Lewis acid catalyzed selective reactions of donor–acceptor cyclopropanes with 2‐naphthols T Kaicharla, T Roy, M Thangaraj, RG Gonnade, AT Biju Angewandte Chemie 128 (34), 10215-10218 , 2016 2016 Citations: 139
Asymmetric N-heterocyclic carbene (NHC)-catalyzed annulation of modified enals with enolizable aldehydes SR Yetra, T Kaicharla, SS Kunte, RG Gonnade, AT Biju Organic Letters 15 (20), 5202-5205 , 2013 2013 Citations: 112
Employing arynes in transition-metal-free monoarylation of aromatic tertiary amines SS Bhojgude, T Kaicharla, AT Biju Organic letters 15 (21), 5452-5455 , 2013 2013 Citations: 102
Practical Synthesis of Phthalimides and Benzamides by a Multicomponent Reaction Involving Arynes, Isocyanides, and CO 2 /H 2 O T Kaicharla, M Thangaraj, AT Biju Organic letters 16 (6), 1728-1731 , 2014 2014 Citations: 93
A Practical and General Diels–Alder Reaction of Pentafulvenes with Arynes SS Bhojgude, T Kaicharla, A Bhunia, AT Biju Organic Letters 14 (16), 4098-4101 , 2012 2012 Citations: 68
Multicomponent reactions involving phosphines, arynes and aldehydes A Bhunia, T Kaicharla, D Porwal, RG Gonnade, AT Biju Chemical Communications 50 (77), 11389-11392 , 2014 2014 Citations: 64
Efficient Diels–Alder Reaction of 1, 2-Benzoquinones with Arynes and Its Utility in One-Pot Reactions T Kaicharla, SS Bhojgude, AT Biju Organic letters 14 (24), 6238-6241 , 2012 2012 Citations: 60
The aryne [2, 3] Stevens rearrangement T Roy, M Thangaraj, T Kaicharla, RV Kamath, RG Gonnade, AT Biju Organic letters 18 (20), 5428-5431 , 2016 2016 Citations: 58
Stereoselective alkyne hydrohalogenation by trapping of transfer hydrogenation intermediates M Das, T Kaicharla, JF Teichert Organic Letters 20 (16), 4926-4929 , 2018 2018 Citations: 53
A Bifunctional Copper Catalyst Enables Ester Reduction with H 2 : Expanding the Reactivity Space of Nucleophilic Copper Hydrides BM Zimmermann, TT Ngoc, DI Tzaras, T Kaicharla, JF Teichert Journal of the American Chemical Society 143 (40), 16865-16873 , 2021 2021 Citations: 48
Using alcohols as simple H 2-equivalents for copper-catalysed transfer semihydrogenations of alkynes T Kaicharla, BM Zimmermann, M Oestreich, JF Teichert Chemical Communications 55 (89), 13410-13413 , 2019 2019 Citations: 42
Employing carboxylic acids in aryne multicomponent coupling triggered by aziridines/azetidines T Roy, SS Bhojgude, T Kaicharla, M Thangaraj, B Garai, AT Biju Organic Chemistry Frontiers 3 (1), 71-76 , 2016 2016 Citations: 42
AgOTf-catalyzed dehydrative [3+ 2] annulation of aziridines with 2-naphthols T Kaicharla, A Jacob, RG Gonnade, AT Biju Chemical Communications 53 (58), 8219-8222 , 2017 2017 Citations: 31
Engaging isatins in solvent-free, sterically congested Passerini reaction T Kaicharla, SR Yetra, T Roy, AT Biju Green chemistry 15 (6), 1608-1614 , 2013 2013 Citations: 27
Metal-free, Brønsted acid-catalyzed formal [3+ 2] annulation of quinone monoacetals with 2-naphthols A Jacob, T Roy, T Kaicharla, AT Biju The Journal of Organic Chemistry 82 (20), 11269-11274 , 2017 2017 Citations: 26
Transition-metal-free synthesis of benzo-fused five-and six-membered heterocycles employing arynes T Kaicharla, AT Biju Green Synthetic Approaches for Biologically Relevant Heterocycles, 45-76 , 2015 2015 Citations: 6
An untethered and formal intermolecular hexadehydro-Diels–Alder reaction: Alkynylboronates with 2-(1, 3-Butadiynyl) pyridines T Kaicharla, M Jin, TR Hoye Journal of the American Chemical Society 146 (50), 34510-34516 , 2024 2024 Citations: 4
Examples Showing the Utility of Doping Experiments in 1 H NMR Analysis of Mixtures T Kaicharla, BS Chinta, TR Hoye The Journal of organic chemistry 87 (9), 5660-5667 , 2022 2022 Citations: 4
Novel conversions of a multifunctional, bio-sourced lactone carboxylic acid T Kaicharla, S Lee, R Wang, AD Pehere, S Xu, TR Hoye ARKIVOC: free online journal of organic chemistry 2, 202312081 , 2023 2023
