@article { ISI:000277274000042, title = {Chemoselective coupling reactions of 5,7-dimethoxyphthalide with the remotely functionalized alkyl iodides: facile racemic synthesis of helicobacter pylori antibiotics}, journal = {Journal of Organic Chemistry}, volume = {75}, number = {9}, year = {2010}, month = {MAY}, pages = {3121-3124}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Highly chemoselective coupling reactions of 5,7-dimethoxyphthalide carbanion with the remotely functionalized long chain alkyl iodides have been demonstrated to accomplish the concise and efficient synthesis of Helicobacter pylori antibiotics, the CJ-molecules, and sporotricale methyl ether.

}, issn = {0022-3263}, doi = {10.1021/jo100168f}, author = {Singh, Mandeep and N. P. Argade} } @article { ISI:000288848900018, title = {Efficient convergent access to spiroketal segment of (+)-spiroxaline methyl ether}, journal = {Synthesis-Stuttgart}, volume = {2}, number = {7}, year = {2011}, month = {APR}, pages = {1137-1141}, publisher = {GEORG THIEME VERLAG KG}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

Starting from trimethylsilylacetylene, a facile synthesis of optically pure spiroketal unit of (+)-spiroxaline methyl ether has been described. The synthesis entails stepwise alkylation and acylation of an alkyne with two different readily available chiral building blocks followed by the reductive in situ regio- and stereoselective spiroketalization pathway.

}, keywords = {(+)-spiroketal segment synthesis, (R)-gamma-valerolactone, (R)-oxirane, alkyne, nucleophilic reactions}, issn = {0039-7881}, doi = {10.1055/s-0030-1258456}, author = {Singh, Mandeep and N. P. Argade} } @article { ISI:000308866800011, title = {Palladium-catalyzed routes to geranylated or farnesylated phenolic stilbenes: synthesis of pawhuskin C and schweinfurthin J}, journal = {Synthesis-Stuttgart}, volume = {44}, number = {18}, year = {2012}, month = {SEP}, pages = {2895-2902}, publisher = {GEORG THIEME VERLAG KG}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

Starting from double MOM-protected phloroglucinol, the facile total syntheses of bioactive natural products pawhuskin C and schweinfurthin J were accomplished in good overall yields. The Heck, Stille, or Suzuki coupling reactions of two different electron-rich phenolic segments bearing geranylated or farnesylated units were involved in the decisive step. The Sonogashira coupling reaction followed by palladium-catalyzed chemo-and stereoselective cis-reduction of an alkyne unit and subsequent isomerization to give the desired natural products is also described.

}, keywords = {geranylated or farnesylated stilbenes, Natural products, palladium-catalyzed coupling reactions, phloroglucinol, Total synthesis}, issn = {0039-7881}, doi = {10.1055/s-0032-1316765}, author = {Singh, Mandeep and N. P. Argade} } @article { ISI:000312003800010, title = {Synthetic studies towards NG-121: diastereoselective synthesis of NG-121 methyl ether}, journal = {Synthesis-Stuttgart}, volume = {44}, number = {24}, year = {2012}, month = {DEC}, pages = {3797-3804}, publisher = {GEORG THIEME VERLAG KG}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

Starting from unsymmetrically O-protected methyl 4-bromo-3,5-dihydroxybenzoate, a facile synthesis of the methyl ether of bioactive natural product NG-121 was accomplished in very good overall yield. The key steps were: Stille coupling reaction of the farnesyl unit with the electron-rich phenolic segment; hydroxy-directed selective epoxidation of the farnesyl chain along with concomitant phenol-driven intramolecular regio- and diastereoselective ring closure to the corresponding hydroxybenzopyran; and regioselective formylation followed by in situ reductive lactonization.

}, keywords = {4-bromo-3, 5-dihydroxybenzoate, formylation, intramolecular cyclization, lactonization, NG-121 methyl ether, Stille coupling}, issn = {0039-7881}, doi = {10.1055/s-0032-1317544}, author = {Singh, Mandeep and N. P. Argade} } @article {46834, title = {Highly efficient chemoselective N-tert butoxycarbonylation of aliphatic/aromatic/heterocyclic amines using diphenylglycoluril as organocatalyst}, journal = {Tetrahedron}, volume = {76}, year = {2020}, month = {JUN }, pages = {131223}, type = {Article}, abstract = {

An efficient approach for the Chemoselective N-tert-butoxycarbonylation of a variety of amines using diphenylglycoluril as organocatalyst has been described. For the first time, a plausible mechanism for the N-tert-butoxycarbonylation has been proposed using density functional theory (DFT) calculations supported by NMR studies. The reusability of the organocatalyst and observation of the desired N-Boc protected amines being formed without the formation of side products like urea, oxazolidinone, isocyanate, and N, N-di-Boc derivatives makes the present protocol desirable. (C) 2020 Elsevier Ltd. All rights reserved.

}, keywords = {DFT studies, Diphenylglycouril, N-tert butoxycarbonylation, organocatalyst, Proton shuttle mechanism}, issn = {0040-4020}, doi = {10.1016/j.tet.2020.131223}, author = {Awasthi, Amardeep and Mukherjee, Anagh and Singh, Mandeep and Rathee, Garima and Vanka, Kumar and Chandra, Ramesh} }