@article { ISI:000319721200042, title = {CuCN-Mediated cascade cyclization of 4-(2-bromophenyl)-2-butenoates: a high-yield synthesis of substituted naphthalene amino esters}, journal = {Journal of Organic Chemistry}, volume = {78}, number = {10}, year = {2013}, month = {MAY}, pages = {5045-5050}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A new method of CuCN-mediated one-pot cyclization of 4-(2-bromophenyl)-2-butenoates leading to efficient synthesis of substituted naphthalene amino esters including phenanthrene aromatic structural units is described. Deuterium labeling studies establish that this one-pot cascade cyclization proceeds through isomerization of olefin, intramolecular C-C bond cyclization, and aromatization as the key intermediates, all occurring in a single step.

}, issn = {0022-3263}, doi = {10.1021/jo400244h}, author = {Reddy, R. Santhosh and Prasad, Pragati K. and Ahuja, Brij Bhushan and Sudalai, Arumugam} } @article {45932, title = {Concise enantioselective synthesis of (2S,3S)-3-hydroxypipecolic acid via proline catalyzed alpha-aminooxylation of aldehydes and Pd-catalyzed ether directed aza-Claisen rearrangements}, journal = {Tetrahedron-Asymmetry}, volume = {26}, year = {2015}, month = {JAN }, pages = {24-28}, type = {Article}, abstract = {

An efficient approach to (2S,3S)-3-hydroxypipecolic acid with an overall yield of 10.2\% and 98\% ee starting from 1,5-pentanediol has been developed. The key steps employed in the synthesis are the D-proline catalyzed sequential alpha-aminooxylation/Horner-Wadsworth-Emmons olefination of an aldehyde and the Pd-catalyzed MOM-ether directed aza-Claisen rearrangement of an allylic trichloroacetimidate. (C) 2014 Elsevier Ltd. All rights reserved.

}, issn = {0957-4166}, doi = {10.1016/j.tetasy.2014.11.010}, author = {Ahuja, Brij Bhushan and Sudalai, Arumugam} } @article { ISI:000354794500012, title = {Cu-catalyzed debrominative cyanation of gem-dibromoolefins: a facile access to alpha,beta-unsaturated nitriles}, journal = {Organic \& Biomolecular Chemistry}, volume = {13}, number = {21}, year = {2015}, month = {APR}, pages = {5918-5923}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

An efficient catalytic route for the synthesis of alpha,beta-unsaturated nitriles from easily accessible gem-dibromoolefins has been developed. The method utilized inexpensive reagents such as Cu2O as a catalyst, L-proline as a ligand and NaCN as a cyanide source to afford alpha,beta-unsaturated nitriles in high yields (62-86\%). A deuterium exchange study has shown that one of the bromide atoms of gem-dibromoolefins exchanges with cyanide while the other with a deuterium atom.

}, issn = {1477-0520}, doi = {10.1039/c5ob00394f}, author = {Ahuja, Brij Bhushan and Sudalai, Arumugam} } @article { ISI:000355354100003, title = {First enantioselective synthesis of (2S,3S)-3-hydroxy-L-arginine via proline catalyzed alpha-aminooxylation of aldehyde and Pd-catalyzed ether-directed aza-Claisen rearrangement}, journal = {Tetrahedron-Asymmetry}, volume = {26}, number = {10-11}, year = {2015}, month = {MAY}, pages = {548-552}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A concise enantioselective synthesis of (2S,3S)-3-hydroxy-L-arginine with an overall yield of 10.9\% and 98\% ee, starting from commercially available 1,4-butanediol in ten linear steps has been achieved. The key chiral inducing steps are D-proline catalyzed sequential alpha-aminooxylation/Horner-Wadsworth-Emmons olefination of an aldehyde and the subsequent diastereoselective MOM-ether-directed Pd-catalyzed aza-Claisen rearrangement of allylic trichloroacetimidate. (C) 2015 Elsevier Ltd. All rights reserved.

}, issn = {0957-4166}, doi = {10.1016/j.tetasy.2015.03.011}, author = {Ahuja, Brij Bhushan and Sudalai, Arumugam} } @article { ISI:000350222400046, title = {One-pot highly enantio- and diastereoselective synthesis of anti,anti vinylic 3-amino-1,2 diols via proline catalyzed sequential alpha-amination/benzoyloxyallylation of aldehydes}, journal = {RSC Advances}, volume = {5}, number = {28}, year = {2015}, month = {FEB}, pages = {21803-21805}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

The first direct asymmetric synthesis of anti, anti vinylic 3-amino-1,2-diols from aldehydes is described via a one-pot sequential L-proline catalyzed alpha-amination/benzoyloxyallylation protocol. The reaction proceeds with exceptionally high diastereoselectivity (\>99\%) as can be explained based on the Felkin-Ahn transition state model. Its effectiveness is proven unambiguously by demonstrating a short asymmetric synthesis of D-ribo-phytosphingosine tetraacetate (93\% ee).

}, issn = {2046-2069}, doi = {10.1039/c5ra02830b}, author = {Ahuja, Brij Bhushan and Sudalai, Arumugam} } @article { ISI:000379437100016, title = {Formal enantioselective synthesis of (-)-epiquinamide by proline-catalyzed one-pot sequential -amination/propargylation of aldehyde and asymmetric dihydroxylation of olefin}, journal = {Synlett}, volume = {27}, number = {11}, year = {2016}, month = {JUL}, pages = {1699-1702}, publisher = {GEORG THIEME VERLAG KG}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

Two independent routes to the formal synthesis of (-)-epiquinamide, have been described: the first route utilizes an l-proline-catalyzed one-pot sequential -amination/propargylation of aldehyde, while the second one employs asymmetric dihydroxylation as the key reaction to install the stereochemistry. While the first synthesis was accomplished in nine steps with 24.4\% overall yield and dr 9:1, the second strategy resulted in the synthesis in eight steps with 36.4\% overall yield and with perfect enantiocontrol.

}, keywords = {Amination, diastereoselective, Dihydroxylation, Proline, quinolizidine}, issn = {0936-5214}, doi = {10.1055/s-0035-1561956}, author = {Ahuja, Brij Bhushan and Emmanuvel, Lourdusamy and Sudalai, Arumugam} } @article { ISI:000369203800013, title = {Pd-catalyzed reductive cleavage of N-N bond in dibenzyl-1-alkylhydrazine-1,2-dicarboxylates with PMHS: application to a formal enantioselective synthesis of (R)-sitagliptin}, journal = {Tetrahedron Letters}, volume = {57}, number = {6}, year = {2016}, month = {FEB}, pages = {684-687}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

An environmentally benign approach involving Pd-catalyzed reductive N-N bond cleavage in dibenzyl-1-alkylhydrazine-1,2-dicarboxylates leading to the synthesis of N-(tert-butoxy)carbamates under very mild conditions has been described. PMHS serves as an inexpensive source of hydride in MeOH/deionized H2O medium. This protocol has been successfully applied in the formal synthesis of (R)-sitagliptin, an anti-diabetic drug. (C) 2015 Elsevier Ltd. All rights reserved.

}, keywords = {anti-Diabetic, Environmentally benign, Hydrazine, PMHS, Reductive cleavage}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2015.12.116}, author = {Dey, Soumen and Gadakh, Sunita K. and Ahuja, Brij Bhushan and Kamble, Sanjay P. and Sudalai, Arumugam} } @inbook {47308, title = {Organocatalyzed α-aminooxylation/amination of aldehydes and their sequential reactions: a versatile tool for the synthesis of bioactive molecules}, booktitle = {Bioactive Natural Products}, volume = {64}, year = {2020}, pages = {417-465}, publisher = {Elsevier B.V.}, organization = {Elsevier B.V.}, abstract = {

This chapter introduces the sequential reactions of proline catalyzed α-aminooxylation and α-amination of aldehydes and its broad applications in the synthesis of bioactive molecules. It starts by presenting an overview of organocatalysis, particularly proline and its catalytic behavior. It then explains the proline catalyzed α-aminooxylation reaction and its sequential reactions one by one along with its applications in the synthesis of natural products. Next, it describes the\ l- and\ d-proline catalyzed α-amination and its sequential reactions. A full description of the synthetic scheme of natural products is provided.

}, doi = {10.1016/B978-0-12-817903-1.00014-0}, author = {Ahuja, Brij Bhushan and Sudalai, Arumugum} }