@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 {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 {49209, title = {Ru-catalyzed asymmetric transfer hydrogenation of racemic /3-keto γ-lactams via dynamic kinetic resolution}, journal = {Tetrahedron}, volume = {167}, year = {2024}, month = {NOV }, pages = {134293}, type = {Article}, abstract = {

The enantioselective transfer hydrogenation of racemic /3-keto gamma-lactams via dynamic kinetic resolution using a chiral Ru(II) catalyst has been developed for the synthesis of optically active /3-hydroxyl lactams with excellent conversion (up to 99 \%), high diastereomeric ratio (dr dr 93:07) and enantiomeric selectivity (89 \% ee ). The reaction proceeded by using HCO2H/Et3N 2 H/Et 3 N as hydrogen donor and features mild, additive free reaction conditions, fast crystallization, broad substrate scope, and an operationally simpler setup than that for molecular hydrogenation.

}, keywords = {(R)-1-((R)-Pyrrolidin-3-yl)ethan-1-ol, /3-keto gamma-lactams, Asymmetric transfer hydrogenation, Dynamic kinetic resolution, Fluroquinolone antibiotics}, issn = {0040-4020}, doi = {10.1016/j.tet.2024.134293}, author = {Malekar, V. Pushpa and More, V. Ganesh and Ramana, V. Chepuri} }