@article {46951, title = {Pd-catalyzed annulation of beta-iodovinyl sulfones with 2-halophenols: a general route for the synthesis of 3-sulfonyl benzofuran derivatives}, journal = {Advanced Synthesis \& Catalysis}, volume = {362}, year = {2020}, month = {MAR}, pages = {1317-1322}, type = {Article}, abstract = {

The palladium-catalyzed annulation between beta-iodovinyl sulfones and 2-halophenols or 1-bromo-2-naphthol or 2-bromo-3-pyridinol is presented. The annulation process involving oxa-Michael addition-elimination and intramolecular Heck reaction leading to form 2,3-disubstituted benzofurans (aryl benzofuryl sulfones) in good to high yields. The regioselective tandem construction of C-O and C-C bonds has been achieved with a variety of substitution patterns. Moreover, the tandem process is reliable at gram-scale reactions and a plausible mechanism is also proposed.

}, keywords = {Benzofurans, beta-Iodovinyl sulfones, Heck reaction, Naphthofurans, oxa-Michael addition}, issn = {1615-4150}, doi = {10.1002/adsc.201901550, Early Access Date = FEB 2020}, author = {Reddy, Raju Jannapu and Kumar, Jangam Jagadesh and Kumari, Arram Haritha and Krishna, Gamidi Rama} } @article {46866, title = {Phenylboronic acid-catalyzed tandem construction of S-S and C-S bonds: a new method for the synthesis of benzyl disulfanylsulfone derivatives from S-benzyl thiosulfonates}, journal = {Organic \& Biomolecular Chemistry}, volume = {18}, year = {2020}, month = {MAY }, pages = {3243-3248}, type = {Article}, abstract = {

A unique phenylboronic acid-catalyzed dimerization-sulfonylation of S-benzyl thiosulfonates has been disclosed. A metal-free tandem construction of S-S and C-S bonds is an operationally simple method to access a wide range of benzyl disulfanylsulfone derivatives in high to excellent yields. Moreover, the robustness of this tandem transformation has been demonstrated by gram-scale reactions, and a plausible mechanism is also proposed.

}, issn = {1477-0520}, doi = {10.1039/d0ob00442a}, author = {Reddy, Raju Jannapu and Waheed, Md and Krishna, Gamidi Rama} } @article {47396, title = {Nickel-catalyzed difunctionalization of alkynyl bromides with thiosulfonates and N-arylthio succinimides: a convenient synthesis of 1,2-thiosulfonylethenes and 1,1-dithioethenes}, journal = {Synthesis-Stuttgart}, year = {2021}, month = {APR }, type = {Article; Early Access}, abstract = {

An efficient nickel-catalyzed vicinal thiosulfonylation of 1bromoalkynes with thiosulfonates in the presence of cesium carbonate is described. An operationally simple and highly regioselective atom transfer radical addition (ATRA) of alkynyl bromides provides a wide range of (E)-1,2-thiosulfonylethenes (alpha-aryl-beta-thioarylvinyl sulfones) in moderate to high yields. The extensive substrate scope of both alkynyl bromides and thiosulfonates is explored with a broad range of functional groups. Indole-derived 1,1- bromoalkenes were also successfully explored in this 1,2-thiosulfonylation process. Moreover, the nickel-catalyzed geminal- dithiolation of alkynyl bromides with N-arylthio succinimides provides 1,1-dithioalkenes in high yields. The present protocol is reliable on gram scale, and a sequential one-pot bromination and thiosulfonylation of phenylacetylene is achieved in a scale-up synthesis. Following control experiments, a plausible mechanism is proposed to rationalize the experimental outcome and the vicinal thiosulfonylation.

}, keywords = {alkynyl bromides, atom transfer radical addition (ATRA), thiosulfonates, thiosulfonylation, vinyl thiosulfones}, issn = {0039-7881}, doi = {10.1055/a-1482-2486, Early Access Date = APR 2021}, author = {Kumari, Arram Haritha and Kumar, Jangam Jagadesh and Krishna, Gamidi Rama and Reddy, Raju Jannapu} } @article {47898, title = {Diethyl phosphite-mediated switchable synthesis of bis(imidazoheterocycles) derived disulfanes and sulfanes using imidazoheterocycles and octasulfur}, journal = {New Journal of Chemistry}, volume = {46}, year = {2022}, month = {MAR }, pages = {4784-4791}, type = {Article}, abstract = {

A practical and highly efficient oxidative dual C-H sulfenylation of imidazoheterocycles using odorless, inexpensive elemental sulfur in DMSO to synthesize sulfur-bridged imidazoheterocycles under metal-free conditions is reported. The amount of diethyl phosphite and sulfur powder most attractively permits a tunable synthesis of bis(imidazoheterocycle)disulfanes and bis(imidazoheterocycle)sulfanes in good to high yields. A comprehensive substrate scope with a broad range of functional group tolerance was realized, and the efficacy of the process was proved at gram-scale reactions. Next, the bis(imidazopyridine)disulfanes were smoothly reacted with various indoles under similar conditions to form the corresponding imidazo[1,2-a]pyridine-indole-derived thioethers in high yields. A plausible mechanism has been proposed based on the control experiments.

}, issn = {1144-0546}, doi = {10.1039/d1nj05226h}, author = {Reddy, Raju Jannapu and Shankar, Angothu and Kumar, Jangam Jagadesh and Sharadha, Nunavath and Krishna, Gamidi Rama} } @article {47599, title = {Interrupted CuAAC-thiolation for the construction of 1,2,3-triazole-fused eight-membered heterocycles from O-/N-propargyl derived benzyl thiosulfonates with organic azides}, journal = {Advanced Synthesis \& Catalysis}, volume = {364}, year = {2022}, month = {JAN}, pages = {319-325}, type = {Article}, abstract = {A copper(I)-catalyzed interrupted click-sulfenylation of O-/N-propargyl benzyl thiosulfonates with organic azides has been disclosed. The unified CuAAC-thiolation provides a wide range of triazole-fused eight-membered heterocycles in good to high (51-94\%) yields under mild reaction conditions. Moreover, a three-component reaction is also achieved involving O-/N-propargyl benzyl thiosulfonates, benzyl bromide, and sodium azide to deliver fused-triazoles in 61-74\% yields. From a synthetic point of view, the present protocol has been demonstrated at gram-scale reactions. A plausible mechanism is also proposed based on experimental results and control experiments.}, keywords = {Eight-Membered Heterocycles, Fused-Triazoles, Interrupted-Click Reaction, Thiolation, thiosulfonates}, issn = {1615-4150}, doi = {10.1002/adsc.202101256}, author = {Reddy, Raju Jannapu and Waheed, Md and Kumari, Arram Haritha and Krishna, Gamidi Rama} } @article {48365, title = {K3PO4-promoted cycloannulation of (E)-beta-Iodovinyl Sulfones with ortho-Hydroxy-chalcones/cinnamates for the synthesis of 2,3,4-trisubstituted 4h-benzopyran derivatives}, journal = {Advanced Synthesis \& Catalysis}, volume = {364}, year = {2022}, month = {DEC }, pages = {4080-4087}, type = {Article}, abstract = {

K3PO4-mediated cycloannulation of (E)-beta-iodovinyl sulfones with ortho-hydroxy chalcones/ortho-hydroxy cinnamates has been realized to access 2,3,4-trisubstituted-4H-benzopyran derivatives. A metal-free tandem oxa-Michael addition and cycloannulation allows the diversity-oriented synthesis of the corresponding 3-sulfonyl-4H-benzopyrans in good to high yields. More importantly, one-pot three-component reaction between (E)-beta-iodovinyl sulfones, 2-hydroxybenzaldehydes, and phosphonium ylides has been established for the synthesis of 4H-chromene derivatives in moderate to good yields. Notably, this metal-free process features a broad substrate scope and easy elaboration into numerous multifaceted chromene products, including bioactive estrone-derivative. The present protocol is sustainable at the gram scale reactions, and post-synthetic applications were also demonstrated. A plausible mechanism is also presented on the basis of existing experimental results.

}, keywords = {(E)-beta-Iodovinyl sulfones, Benzopyrans, Cycloannulation, ortho-Hydroxy Chalcones, Sulfones}, issn = {1615-4150}, doi = {10.1002/adsc.202200763}, author = {Reddy, Raju Jannapu and Kumar, Jangam Jagadesh and Krishna, Gamidi Rama} } @article {48001, title = {Solvent-driven mono- and bis-sulfenylation of (E)-beta-iodovinyl sulfones with thiols for flexible synthesis of 1,2-thiosulfonylalkenes and 1,2-dithioalkenes}, journal = {Journal of Organic Chemistry}, volume = {87}, year = {2022}, month = {MAR}, pages = {3934-3951}, type = {Article}, abstract = {

The nature of solvent is a key factor for stereoselective mono-and bis-thiolation of (E)-beta-iodovinyl sulfones with thiols under basic conditions. A novel and unprecedented vicinal bisthiolation of (E)-beta-iodovinyl sulfones with thiols under the influence of K2CO3/DMSO at room temperature for quick assembly of (E)-1,2-dithio-1-alkenes is presented. Solvent-induced stereoselective monosulfenylation of (E)-beta-iodovinyl sulfones with thiols has also been established for the synthesis of both (E)- and (Z)-1,2-thiosulfonylethenes in MeCN and MeOH, respectively. Moreover, K2CO3-mediated desulfonylative-sulfenylation of (Z)-1,2-thiosulfonylethenes with thiols in DMSO furnished unsymmetrical (Z)-1,2-dithio-1-alkenes for the first time. The solvent-dependent versatile reactivity of (E)-beta-iodovinyl sulfones has been successfully explored to provide a set of (E)-/(Z)-1,2-dithio-1-alkenes and (E)-/(Z)-1,2-thiosulfonyl-1-alkenes in good to high yields with excellent stereoselectivities. Notably, this operationally simple process utilizes a broad substrate scope with good functional group tolerance and compatibility. The efficacy of the process has been proven for gram-scale reactions, and plausible mechanistic models are outlined on the basis of experimental results and control experiments.

}, issn = {0022-3263}, doi = {10.1021/acs.joc.1c02444}, author = {Reddy, Raju Jannapu and Kumari, Arram Haritha and Sharadha, Nunavath and Krishna, Gamidi Rama} } @article {48783, title = {Pd(II)-catalyzed tandem cycloannulative-alkenylation of o-alkynyl-phenols/anilines with (E)-β-Iodovinyl sulfones: a direct strategy to construct 3-(Vinyl sulfonyl)benzoheterole derivatives}, journal = {Journal of Organic Chemistry}, volume = {88}, year = {2023}, month = {JUN }, pages = {8889-8903}, type = {Article}, abstract = {

Benzoheterolesand vinyl sulfones are the most promisingpharmaceuticalrelevance motifs, yet the hybrid analogues of these scaffolds stillneed to be explored. We report herein a general and highly efficientPd(OAc)(2)-catalyzed intramolecular cyclization and vinylationof o-alkynylphenols/o-alkynylanilineswith (E)-beta-iodovinyl sulfones under mild reactionconditions. A direct C(sp(2))-C(sp(2)) cross-couplingis enabled for the diversity-oriented synthesis of vinyl sulfone-tetheredbenzofurans and indoles in good to high yields with excellent stereoselectivity.Notably, this tandem process was consistent at the gram scale, andin situ, generation of 2-(phenylethynyl)phenol has also been utilizedin a scalable synthesis. Late-stage synthetic transformations werealso further explored, including isomerization and desulfonylative-sulfenylation.Moreover, several control experiments were accomplished, and we proposeda plausible mechanism based on existing experimental results.

}, issn = {0022-3263}, doi = {10.1021/acs.joc.3c00671}, author = {Reddy, Raju Jannapu and Sharadha, Nunavath and Krishna, Gamidi Rama} }