@article {46292, title = {One-pot Au [III]-/lewis acid catalyzed cycloisomerization of nitroalkynes and [3+3]cycloaddition with donor-acceptor cyclopropanes}, journal = {Organic Letters}, volume = {21}, year = {2019}, month = {AUG}, pages = {6221-6224}, type = {Article}, abstract = {

A one-pot protocol for the synthesis of a tricyclic pseudoindoxyl scaffold from 2-nitroalkynylbenzenes, comprising of an Au(III)-catalyzed nitroalkyne cycloisomerization leading to isatogen and its [3 + 3]-cycloaddition with donor-acceptor cyclopropanes mediated by a suitable Lewis acid, has been developed.

}, issn = {1523-7060}, doi = {10.1021/acs.orglett.9b02035}, author = {Dhote, Pawan S. and Ramana, V. Chepuri} } @article {46686, title = {Oxidative rearrangement of stilbenes to 2,2-diaryl-2-hydroxyacetaldehydes}, journal = {ACS Omega}, volume = {5}, year = {2020}, month = {OCT }, pages = {25199-25208}, type = {Article}, abstract = {

A one-pot oxone-mediated/iodine-catalyzed oxidative rearrangement of stilbenes leading to 2,2-diary1-2-hydroxyacetaldehydes is described. Control experiments revealed that a 2,2-diarylacetaldehyde was initially formed that undergoes subsequent alpha-hydroxylation. The resulting alpha-hydroxyaldehydes have been subjected to a one-pot Still Gennari olefination followed by cyclization, leading to S,S-diaryl-y-butenolides.

}, issn = {2470-1343}, doi = {10.1021/acsomega.0c03328}, author = {Kalshetti, Rupali G. and Ramana, V. Chepuri} } @article {47047, title = {Ru-catalyzed asymmetric transfer hydrogenation of alpha-acyl butyrolactone via dynamic kinetic resolution: asymmetric synthesis of bis-THF alcohol intermediate of darunavir}, journal = {Tetrahedron Letters}, volume = {66}, year = {2021}, month = {MAR }, pages = {152831}, type = {Article}, abstract = {

The Ru-catalyzed enantio- and diastereoselective dynamic kinetic resolution of alpha-(benzyloxy/benzoyloxy)acyl-gamma-butyrolactones has been examined via transfer hydrogenation. Employing the in situ prepared (R,R)-Ru-FsDPEN catalyst, the transfer hydrogenation of using formic acid/triethylamine at rt gave the corresponding (S)-3-((S)-2-(benzyloxy/benzoyloxy)-1-hydroxyethyl)dihydrofuran-2(3H)-on e with good to excellent diastereo- and enantioselectivity. One of the resulting hydrogenation product prepared on gram scales was utilized for the synthesis of (3R,3aS,6aR)-hexahydrofuro[2,3-b]furan-3-ol (1), a key synthetic intermediate of various HIV protease inhibitors such as darunavir with excellent enantio-(95\% ee) and diastereoselectivities (dr 95:5). (C) 2021 Elsevier Ltd. All rights reserved.

}, keywords = {Bis-THF-OH intermediate, Darunavir, Dynamic kinetic resolution, Ru-catalysis, transfer hydrogenation}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2021.152831}, author = {More, V. Ganesh and Malekar, V. Pushpa and Kalshetti, Rupali G. and Shinde, Mahesh H. and Ramana, V. Chepuri} } @article {47657, title = {Synthesis of anisotropic rod-like gold nanostructures in organic media (vol 133, 106, 2021)}, journal = {Journal of Chemical Sciences}, volume = {133}, year = {2021}, month = {DEC}, pages = {120}, type = {Correction}, issn = {0974-3626}, doi = {10.1007/s12039-021-01992-5}, author = {Prasad, V. Bhagavatula L. and Sivasankaran, Prathap Chandran and Patel, Pitambar and Malekar, V. Pushpa and Maya, V. K. and Ramana, V. Chepuri} } @article {47893, title = {Competing intra- vs intermolecular nitrene transfer in the [Au]-catalysed reaction of 2-alkynylphenylazides}, journal = {Advanced Synthesis \& Catalysis}, volume = {364}, year = {2022}, month = {MAR}, pages = {1122-1133}, type = {Article}, abstract = {

The possibility of interrupting the gold-catalysed intramolecular cyclization of 2-alkynylphenylazide derivatives, employing known nitrene transfer reagents such as anthranil and its isomer 1,2-benzisoxazole, has been attempted in search of developing simple tools for product diversification. With 1,2-benzisoxazoles, the intermolecular nitrene transfer leading to quinazoline is competitive with intramolecular azidoalkyne cyclization resulting in spiro indol-3-ylidene derivatives. However, in case of the reaction in the presence of anthranil, both intra- and intermolecular nitrene transfer processes result in the same product indol-3-ylidene.

}, keywords = {2-Benzisoxazole, Anthranil and 1, Gold catalysis, Nitrene Transfer, Quinazoline}, issn = {1615-4150}, doi = {10.1002/adsc.202101412}, author = {Dhote, Pawan S. and Ramana, V. Chepuri} } @article {48050, title = {Facile synthesis of the spiro-pyridoindolone scaffold via a gold-catalysed intramolecular alkynol cyclisation/hydroindolylation}, journal = {Organic \& Biomolecular Chemistry}, volume = {20}, year = {2022}, month = {MAR}, pages = {d1ob02483c}, type = {Article}, abstract = {

A simple approach for the synthesis of pyridoindolone scaffolds with a spiroannulated tetrahydrofuran ring is described. The overall process comprises intramolecular sequential gold-catalysed 5-endo-dig alkynol cycloisomerization and subsequent addition of indole C2 to the in situ generated oxocarbenium cation.

}, issn = {1477-0520}, doi = {10.1039/d1ob02483c}, author = {Shinde, Mahesh H. and Ramana, V. Chepuri} } @article {48378, title = {Rediscovering Bacon{\textquoteright}s hydrazine/phenylhydrazine mediated cyclization of 2,2 {\textquoteleft}-dicarbonylbi(hetero)aryls: construction of (5-azo)-/indazolo[2,3-a]quinolines}, journal = {Organic \& Biomolecular Chemistry}, volume = {20}, year = {2022}, month = {JAN}, pages = {636-648}, type = {Article}, abstract = {

Hydrazine/phenylhydrazine-mediated reductive dicarbonyl coupling reactions have been carried out under mild conditions to provide polycyclic aromatic compounds and azo-substituted polyaromatic compounds. This method has a broad substrate scope with good functional group compatibility.

}, issn = {1477-0520}, doi = {10.1039/d1ob02207e}, author = {Dhote, Pawan S. and Ramana, V. Chepuri} } @article {47985, title = {Synthesis of central spiro-bis-THF fragments of symbiospirols A-C}, journal = {New Journal of Chemistry}, volume = {46}, year = {2022}, month = {JUL}, pages = {13738-13744}, type = {Article}, abstract = {

The gold catalysed alkynediol spiroketalization to assemble the central spiro-bis-THF fragments (C22-C33 and C36-C47) of symbiospirols A-C is documented. The adopted chiral pool approach employed commercially available d-glucose and l-malic acid in the synthesis of key building blocks. In addition, two other possible diastereomers have been synthesized in order to establish the relative stereochemistry of the unassigned THF-center of symbiospirols B/C.

}, issn = {1144-0546}, doi = {10.1039/d2nj02227c}, author = {Shinde, Mahesh H. and Kona, Chandrababu N. and Ramana, V. Chepuri} }