@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 {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 {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} }