@article { ISI:000318393000028, title = {N-Heterocyclic carbene catalyzed oxidative stannylation of aldehydes: a facile entry to organotin(IV) carboxylates}, journal = {Tetrahedron Letters}, volume = {54}, number = {21}, year = {2013}, month = {MAY}, pages = {2679-2681}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A simple protocol is described for the oxidative transformation of aldehydes to the corresponding organotin(IV) carboxylates in high yields (up to 90\%) that utilizes atmospheric O-2 as the sole oxidant, N-heterocyclic carbene as catalyst (at 10 mol \%), and tributyl tin chloride as stannylating agent. The uniqueness of the reaction lies in the direct conversion of aldehydes to the corresponding organotin(IV) carboxylates via stannylation of carboxylic acids, generated from the reaction of a Breslow intermediate with O-2. (c) 2013 Elsevier Ltd. All rights reserved.

}, keywords = {Carboxylic acid stannanes, N-Heterocyclic carbene, Oxidative stannylation, oxygen, Tributyltin chloride}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2013.03.050}, author = {Reddi, Rambabu N. and Malekar, Pushpa V. and Sudalai, Arumugam} } @article { ISI:000325194900006, title = {N-Heterocyclic carbene catalyzed regioselective oxo-acyloxylation of alkenes with aromatic aldehydes: a high yield synthesis of alpha-acyloxy ketones and esters}, journal = {Organic \& Biomolecular Chemistry}, volume = {11}, number = {38}, year = {2013}, month = {OCT}, pages = {6477-6482}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

An N-heterocyclic carbene (NHC)-catalyzed reaction of alkenes with aromatic aldehydes providing for a high yield synthesis of alpha-acyloxy ketones and esters has been described. This unprecedented regioselective oxidative process employs NBS and Et3N in stoichiometric amounts and O-2 (1 atm) as an oxidant under ambient conditions in DMSO as a solvent.

}, issn = {1477-0520}, doi = {10.1039/c3ob41551a}, author = {Reddi, Rambabu N. and Malekar, Pushpa V. and Sudalai, Arumugam} } @article { ISI:000344635200043, title = {I-2-catalyzed regioselective Oxo- and hydroxy-acyloxylation of alkenes and enol ethers: a facile access to alpha-acyloxyketones, esters, and diol derivatives}, journal = {Organic Letters}, volume = {16}, number = {21}, year = {2014}, month = {NOV}, pages = {5674-5677}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

I-2-catalyzed oxo-acyloxylation of alkenes and enol ethers with carboxylic acids providing for the high yield synthesis of a-acyloxyketones and esters is described. This unprecedented regioselective oxidative process employs TBHP and Et3N in stoichiometric amounts under metal-free conditions in DMSO as solvent. Additionally, I-2-catalysis allows the direct hydroxy-acyloxylation of alkenes with the sequential addition of BH3 center dot SMe2 leading to monoprotected diol derivatives in excellent yields.

}, issn = {1523-7060}, doi = {10.1021/ol5027393}, author = {Reddi, Rambabu N. and Prasad, Pragati K. and Sudalai, Arumugam} } @article { ISI:000367722500058, title = {N-Heterocyclic carbene catalyzed oxidative coupling of alkenes/alpha-bromoacetophenones with aldehydes: a facile entry to alpha,beta-epoxy ketones}, journal = {Angewandte Chemie-International Edition}, volume = {54}, number = {47}, year = {2015}, month = {NOV}, pages = {14150-14153}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {

{A novel, N-heterocyclic carbene (NHC) catalyzed direct oxidative coupling of styrenes with aldehydes has been described for the synthesis of alpha,beta-epoxy ketones in good yields. This unprecedented regioselective oxidative coupling employs NBS/DBU/DMSO (DBU = 1,8-diazabicyclo [5.4. 0] undec-7-ene

}, keywords = {aldehydes, epoxidation, N-heterocyclic carbenes, Oxidation, synthetic methods}, issn = {1433-7851}, doi = {10.1002/anie.201507363}, author = {Reddi, Rambabu N. and Prasad, Pragati K. and Sudalai, Arumugam} } @article { ISI:000372175300004, title = {I-2-mediated regioselective C-3 azidation of indoles}, journal = {Organic \& Biomolecular Chemistry}, volume = {14}, number = {11}, year = {2016}, month = {FEB}, pages = {3027-3030}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

An unprecedented synthesis of novel 3-azido indoles has been developed using I-2 and NaN3 in high yields and excellent regio-selectivity. The reaction proceeds under metal-free conditions at room temperature. Essentially, an umpolung in reactivity at the C-3 position of indole has been achieved by the activation of indoles with I-2.

}, issn = {1477-0520}, doi = {10.1039/c6ob00295a}, author = {Prasad, Pragati K. and Kalshetti, Rupali G. and Reddi, Rambabu N. and Kamble, Sanjay P. and Sudalai, Arumugam} } @article { ISI:000369072900005, title = {N-heterocyclic-carbene-catalyzed regioselective oxidative ring-opening of epoxides with aromatic aldehydes: a facile entry to alpha-acyloxyketones}, journal = {Asian Journal of Organic Chemistry}, volume = {5}, number = {1}, year = {2016}, month = {JAN}, pages = {48-51}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {

A high-yielding synthesis of -acyloxyketones using a N-heterocyclic-carbene (NHC)-catalyzed, oxidative ring-opening of epoxides with aromatic aldehydes is described. This regioselective, oxidative process utilizes a N-bromosuccinimide (NBS)/DMSO combination as the oxidant system and Et3N as the base under mild reaction conditions.

}, keywords = {aldehydes, epoxides, halogen oxidants, N-heterocyclic carbenes, oxygen}, issn = {2193-5807}, doi = {10.1002/ajoc.201500355}, author = {Reddi, Rambabu N. and Gontala, Arjun and Prasad, Pragati K. and Sudalai, Arumugam} } @article { ISI:000369771800040, title = {Regioselective oxo-amination of alkenes and enol ethers with N-bromosuccinimide-dimethyl sulfoxide combination: a facile synthesis of alpha-amino-ketones and esters}, journal = {Organic Letters}, volume = {18}, number = {3}, year = {2016}, month = {FEB}, pages = {500-503}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

An unprecedented conversion of alkenes and enol ethers to the corresponding a-imido carbonyl compounds with excellent regioselectivity and yields has been developed. This oxo-amination process employs readily available N-bromosuccinimide (NBS) and secondary amines as N-sources and dimethyl sulfoxide (DMSO) as the oxidant and also leads to the production of amino alcohols in a single step on reduction, thus broadening the scope of this operationally simple reaction. For the first time, the formation of reactive Me2S+-O-Br species generated by the interaction of NBS with DMSO has been proven.

}, issn = {1523-7060}, doi = {10.1021/acs.orglett.5b03540}, author = {Prasad, Pragati K. and Reddi, Rambabu N. and Sudalai, Arumugam} } @article {43484, title = {Concise enantioselective synthesis of 1,4-dideoxy-1,4-imino-D-arabinitol using Co(III)(salen)-catalyzed hydrolytic kinetic resolution of a two-stereocentered anti-azido epoxide}, journal = {Tetrahedron-Asymmetry}, volume = {28}, year = {2017}, month = {JAN}, pages = {162-165}, abstract = {A concise enantioselective synthesis of 1,4-dideoxy-1,4-imino-D-arabinitol, (+)-DAB-1, has been described in good overall yield (18.1\%) and with high enantiomeric purity (up to 98\% ee) starting from a simple raw material, cis-2-butene-1,4-diol. The Co-catalyzed hydrolytic kinetic resolution of a two-stereocentered racemic azido epoxide followed by asymmetric dihydroxylation of the alkene and {\textquoteright}one pot{\textquoteright} reductive cyclisation of the azido diol are key reactions in the synthetic sequence. (C) 2016 Elsevier Ltd. All rights reserved.}, doi = {10.1016/j.tetasy.2016.10.013}, author = {Reddi, Rambabu N. and Prasad, Pragati K. and Kalshetti, Rupali G. and Sudalai, Arumugam} } @article {48008, title = {Studies toward the total synthesis of (+)-neopeltolide using N-heterocyclic carbene-catalyzed oxo-acyloxylation/reductive oxa-Michael addition strategy}, journal = {Bulletin of the Korean Chemical Society}, volume = {43}, year = {2022}, month = {OCT}, pages = {1169-1172}, type = {Article}, abstract = {

This article describes a concise synthesis of two important fragments (tetrahydropyran [THP] and ketone moieties) of the cytotoxic macrolide (+)-neopeltolide in 10 long linear steps in enantiomerically pure form. Asymmetric Keck allylation to install the required C11 and C13 stereocenters, N-heterocyclic carbene (NHC)-catalyzed oxoacyloxylation to functionalize alkenes, and reductive oxa-Michael addition to construct 2,6-difunctionalized THP unit intramolecularly are the important steps in synthetic efforts. Finally, Keck asymmetric allylation and Lewis acid-catalyzed diastereoselective allylation of the aldehyde were sequentially employed to establish the stereocenters at C11 and C13 positions, respectively.

}, keywords = {(+)-neopeltolide, Keck allylation, Macrolide, NHC-catalyzed oxoacyloxylation, reductive oxa-Michael addition}, issn = {0253-2964}, doi = {10.1002/bkcs.12604}, author = {Reddi, Rambabu N. and Sudalai, Arumugam and Jo, Changbum} }