@article { ISI:000348510400004, title = {Catalyst-dependent selectivity in the relay catalytic branching cascade}, journal = {Chemistry-A European Journal}, volume = {21}, number = {6}, year = {2015}, month = {FEB}, pages = {2319-2323}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

The synthesis of small organic molecules as probes for discovering new therapeutic agents has been an important aspect of chemical biology. One of the best ways to access collections of small molecules is to use various techniques in diversity-oriented synthesis (DOS). Recently, a new form of DOS, namely relay catalytic branching cascades (RCBCs), has been introduced, wherein a common type of starting material reacts with several scaffold-building agents (SBAs) to obtain structurally diverse molecular scaffolds under the influence of catalysts. Herein, the RCBC reaction of a common type of substrate with SBAs is reported to give two different types of molecular scaffolds and their formation is essentially dependent on the type of catalyst used.

}, keywords = {alkynols, cascade synthesis, chemoselectivity, diversity-oriented synthesis, Homogeneous catalysis}, issn = {0947-6539}, doi = {10.1002/chem.201405736}, author = {Bansode, Avinash H. and Shaikh, Aslam C. and Kavthe, Rahul D. and Thorat, Shridhar and Gonnade, Rajesh G. and Patil, Nitin T.} } @article { ISI:000363666000023, title = {Highly emissive organic solids with remarkably broad color tunability based on N,C-chelate, four-coordinate organoborons}, journal = {Chemical Communications}, volume = {51}, number = {89}, year = {2015}, month = {SEP}, pages = {16115-16118}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Molecular fluorophores based on N,C-chelate, four-coordinate organo-borons exhibit tunable solid-state emission colors that cover the whole visible region from blue to red. The emission color can be tuned through the substituents on either quinolines or the boron center.

}, issn = {1359-7345}, doi = {10.1039/c5cc06351e}, author = {Shaikh, Aslam C. and Ranade, Dnyanesh S. and Thorat, Shridhar and Maity, Arunava and Kulkarni, Prasad P. and Gonnade, Rajesh G. and Munshi, Parthapratim and Patil, Nitin T.} } @article { ISI:000358370700007, title = {Identifying solid luminogens through gold-catalysed intramolecular hydroarylation of alkynes}, journal = {European Journal of Organic Chemistry}, number = {22}, year = {2015}, month = {AUG}, pages = {4860-4867}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {

The identification of a new class of luminogens based on pyrrolo-quinoxaline embedded coumarin (PQC) structures is reported. The reaction relies on the gold-catalyzed hydroarylation reaction of appropriately substituted aryl alkynoates that produces molecules that exhibit solvatochromism and aggregation-induced emission enhancement (AIEE) phenomena. The application of PQCs for live cell imaging has also been demonstrated.

}, keywords = {Cell imaging, Dyes/pigments, fluorescence, Gold, Luminescence, Solvatochromism}, issn = {1434-193X}, doi = {10.1002/ejoc.201500503}, author = {Shaikh, Aslam C. and Shalini, S. and Vaidhyanathan, Ramanathan and Mane, Manoj V. and Barui, Ayan Kumar and Patra, Chitta Ranjan and Venkatesh, Yeduru and Bangal, Prakriti Ranjan and Patil, Nitin T.} } @article { ISI:000378390300022, title = {Efficient access to alkynylated quinalizinones via the gold(I)-catalyzed aminoalkynylation of alkynes}, journal = {Chemical Communications}, volume = {52}, number = {52}, year = {2016}, month = {MAY}, pages = {8152-8155}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

The gold-catalyzed aminoalkynylation of alkynes for the synthesis of quinalizinones is reported. For instance, the reaction of pyridinoalkynes with 1-[(triisopropylsilyl)-ethynyl]-1,2-benziodoxol-3(1H)-one (TIPS-EBX) in the presence of a catalytic amount of AuCl at 50 8C afforded alkynylated quinalizinones in 57-87\% yields.

}, issn = {1359-7345}, doi = {10.1039/c6cc03414d}, author = {Shinde, Popat S. and Shaikh, Aslam C. and Patil, Nitin T.} } @article { ISI:000371754000043, title = {Gold vs rhodium catalysis: tuning reactivity through catalyst control in the C-H alkynylation of isoquinolones}, journal = {Organic Letters}, volume = {18}, number = {5}, year = {2016}, month = {MAR}, pages = {1056-1059}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A site-selective C-4/C-8 alkynylation of isoquinolones catalyzed by gold and rhodium complexes is reported. A broad range of synthetically useful functional groups (-F, -Cl, -Br, -CF3, -OMe, alkyl, etc.) were tolerated, providing an efficient and robust protocol for the synthesis either C-4- or C-8-alkynylated isoquinolones.

}, issn = {1523-7060}, doi = {10.1021/acs.orglett.6b00175}, author = {Shaikh, Aslam C. and Shinde, Dinesh R. and Patil, Nitin T.} } @article {42843, title = {Oxidative intramolecular 1,2-amino-oxygenation of alkynes under Au(I)/Au(III)-catalysis: discovery of pyridinium-oxazole dyad as novel lonic fluorophore}, journal = {Angewandte Chemie International Edition}, year = {2016}, month = {JAN}, doi = {10.1002/anie.201609335R1}, author = {Shaikh, Aslam C. and Ranade, Dnyanesh S. and Rajamohanan, Pattuparambil R. and Kulkarni, Prasad P. and Patil, Nitin T.} } @article {43360, title = {Oxidative intramolecular 1,2-amino-oxygenation of alkynes under Au I /Au III catalysis: discovery of a pyridinium-oxazole dyad as an ionic fluorophore}, journal = {Angewandte Chemie-International Edition}, volume = {56}, year = {2017}, month = {JAN}, pages = {757 - 761}, doi = {10.1002/ange.201609335}, author = {Shaikh, Aslam C. and Ranade, Dnyanesh Sadanand and Rajamohanan, Pattuparambil R. and Kulkarni, Prasad Padmakar and Patil, Nitin T.} } @article {43482, title = {Oxidative intramolecular 1,2-amino-oxygenation of alkynes under Au-I/Au-III catalysis: discovery of a pyridinium-oxazole dyad as an ionic fluorophore}, journal = {Angewandte Chemie-International Edition}, volume = {56}, year = {2017}, month = {JAN}, pages = {757-761}, abstract = {Oxidative intramolecular 1,2-amino-oxygenation reactions, combining gold(I)/gold(III) catalysis, is reported. The reaction provides efficient access to a structurally unique ionic pyridinium-oxazole dyad with tunable emission wavelengths. The application of these fluorophores as potential biomarkers has been investigated.}, doi = {10.1002/anie.201609335}, author = {Shaikh, Aslam C. and Ranade, Dnyanesh S. and Rajamohanan, Pattuparambil R. and Kulkarni, Prasad P. and Patil, Nitin T.} } @article {45428, title = { Accessing alpha-arylated nitriles via BF3 center dot OEt2 catalyzed cyanation of para-quinone methides using tert-butyl isocyanide as a cyanide source}, journal = {Journal of Organic Chemistry}, volume = {83}, year = {2018}, month = {OCT}, pages = {12305-12314}, type = {Article}, abstract = {BF3 center dot OEt2 catalyzed 1,6-conjugate addition of tertbutyl isocyanide to para-quinone methides and fuchsones for the synthesis of alpha-diaryl and alpha-triaryl nitriles has been reported. This protocol allows alpha-diaryl- and alpha-triaryl nitriles to be accessed in good to excellent yields and with a broad substrate scope, which could be further functionalized to give a versatile set of products. This is the first example wherein tert-butyl isocyanide has been used as a cyanide source for the 1,6-conjugate addition.}, issn = { 0022-3263}, doi = {10.1021/acs.joc.8b01926}, author = {Shirsath, Sachin R. and Shinde, Ganesh H. and Shaikh, Aslam C. and Muthukrishnan, M.} } @article {45399, title = { A new class of N-doped ionic PAHs via intramolecular [4+2]-cycloaddition between arylpyridines and alkynes}, journal = {Chemical Communications}, volume = {54}, year = {2018}, month = {OCT}, pages = {11909-11912}, type = {Article}, abstract = {Reported herein, for the first time, is a copper-promoted intramolecular [4+2]-cycloaddition cascade to access ionic N-doped polycyclic aromatic hydrocarbons (PAHs) with tunable emission wavelengths. It is shown that the reaction can be made catalytic with respect to Cu(OTf)(2) when an external oxidant, Selectfluor, was used.}, issn = { 1359-7345}, doi = {10.1039/c8cc05743e}, author = {Mule, Ravindra D. and Shaikh, Aslam C. and Gade, Amol B. and Patil, Nitin T.} } @article {44468, title = {Transition metal free regio-selective C{\textendash}H hydroxylation of chromanones towards the synthesis of hydroxyl-chromanones using PhI(OAc)2 as the oxidant}, journal = {Chemical Communications}, volume = {54}, year = {2018}, month = {FEB}, pages = {2252-2255}, type = {Journal Article}, abstract = {

The chromanone scaffold is considered as a privileged structure in drug discovery. Herein, we report a highly efficient PhI(OAc)2 mediated regioselective, direct C{\textendash}H hydroxylation of chromanones. This method offers easy access to substituted 6-hydroxy chromanones in moderate to good isolated yields, thus paving the way for their pharmaceutical studies.

}, issn = {13597345}, doi = {10.1039/C7CC08588E}, author = {Viswanadh, N.}, editor = {Ghotekar, Ganesh S.} } @article {46142, title = {External oxidant-dependent reactivity switch in copper-mediated intramolecular carboamination of alkynes: access to a different class of fluorescent ionic nitrogen-doped polycyclic aromatic hydrocarbons}, journal = {Journal of Organic Chemistry}, volume = {84}, year = {2019}, month = {APR }, pages = {4120-4130}, type = {Article}, abstract = {

An interesting case of external oxidant-controlled reactivity switch leading to a divergent set of ionic nitrogen-doped polycyclic aromatic hydrocarbons (N-doped PAHs), is presented here, which is quite unrecognized in copper-mediated reactions. In the current scenario, from the same pyridino-alkyne substrates, the use of the external oxidant Ph1(0Ac)2, in combination with Cu(OTf)(2), gave N-doped spiro-PAHs via a dearomative 1,2-carboamination process; whereas, without the use of oxidant, an alkyne/azadiene [4 + 2]-cycloaddition cascade occurred to exclusively afford ionic N-doped PAHs. These newly synthesized N-doped PAHs further exhibit tunable emissions, as well as excellent quantum efficiencies.

}, issn = {0022-3263}, doi = {10.1021/acs.joc.9b00120}, author = {Shaikh, Aslam C. and Banerjee, Somsuvra and Mule, Ravindra D. and Bera, Saibal and Patil, Nitin T.} } @article {46192, title = {Ionic pyridinium-oxazole dyads: design, synthesis, and application in mitochondrial imaging}, journal = {Journal of Organic Chemistry}, volume = {84}, year = {2019}, month = {FEB }, pages = {1766-1777}, type = {Article}, abstract = {

We recently developed an oxidative intramolecular 1,2-amino-oxygenation reaction, combining gold(I)/gold(III) catalysis, for accessing structurally unique ionic pyridinium-oxazole dyads (PODs) with tunable emission wavelengths. On further investigation, these fluorophores turned out to be potential biomarkers; in particular, the one containing -NMe2 functionality (NMe2-POD) was highly selective for mitochondrial imaging. Of note, because of mitochondria{\textquoteright}s involvement in early-stage apoptosis and degenerative conditions, tracking the dynamics of mitochondrial morphology with such imaging technology has attracted much interest. Along this line, we wanted to build a library of such PODs which are potential mitochondria trackers. However, Au/Selecfluor, our first-generation catalyst system, suffers from undesired fluorination of electronically rich PODs resulting in an inseparable mixture (1:1) of the PODs and their fluorinated derivatives. In our attempt to search for a better alternative to circumvent this issue, we developed a second-generation approach for the synthesis of PODs by employing Cu(II)/PhI(OAC)(2)-mediated oxidative 1,2-amino-oxygenation of alkynes. Thes newly synthesized PODs exhibit tunable emissions as well as excellent quantum efficiency up to 0.96. Further, this powerful process gives rapid access to a library of NMe2-PODs which are potential mitochondrial imaging agents. Out of the library, the randomly chosen POD-3g was studied for cell-imaging experiments which showed high mitochondrial specificity, superior photostability, and appreciable tolerance to microenvironment changes with respect to commercially available MitoTracker green.

}, issn = {0022-3263}, doi = {10.1021/acs.joc.8b02528}, author = {Shaikh, Aslam C. and Varma, Mokshada E. and Mule, Ravindra D. and Banerjee, Somsuvra and Kulkarni, Prasad P. and Patil, Nitin T.} } @article {46349, title = {Oxone promoted dehydrogenative Povarov cyclization of N-aryl glycine derivatives: an approach towards quinoline fused lactones and lactams}, journal = {RSC Advances}, volume = {9}, year = {2019}, month = {SEP }, pages = {30277-30291}, type = {Article}, abstract = {

Oxone promoted intramolecular dehydrogenative imino Diels-Alder reaction (Povarov cyclization) of alkyne tethered N-aryl glycine esters and amides has been explored, thus affording biologically significant quinoline fused lactones and lactams. The reaction is simple, scalable, and high yielding (up to 88\%). The method was further extended to prepare biologically important luotonin-A analogues and the quinoline core of uncialamycin.

}, doi = {10.1039/c9ra06212b}, author = {More, Devidas A. and Shinde, Ganesh H. and Shaikh, Aslam C. and Muthukrishnan, M.} } @article {46195, title = {Transition-metal-free benzannulation of tricarbonyl derivatives with arynes: access to 1,3-dinaphthol precursors for the synthesis of rhodamine dye analogues}, journal = {Journal of Organic Chemistry}, volume = {84}, year = {2019}, month = {FEB}, pages = {2269-2276}, type = {Article}, abstract = {

Herein, we report a transition-metal-free annulation reaction of benzynes and 1,3-oxopentanedioate for the synthesis of highly functionalized naphthalene derivatives for the first time. Additionally, the representative naphthalene derivatives have been successfully transformed into the new series of rhodamine dye analogues.

}, issn = {0022-3263}, doi = {10.1021/acs.joc.8b02560}, author = {Ghotekar, Ganesh S. and Shaikh, Aslam C. and Muthukrishnan, M.} } @article {46865, title = {1,6-Conjugate addition initiated formal [4+2] annulation of p-quinone methides with sulfonyl allenols: a unique access to spiro[5.5]undeca-1,4-dien-3-one scaffolds}, journal = {Chemical Communications}, volume = {56}, year = {2020}, month = {MAY }, pages = {5022-5025}, type = {Article}, abstract = {

An expedient one-pot synthesis of carbocyclic spiro[5.5]undeca-1,4-dien-3-ones via 1,6-conjugate addition initiated formal [4+2] annulation sequences by employing p-quinone methides and sulfonyl allenols is presented. Furthermore, this synthetic protocol tolerates a wide variety of p-quinone methides and sulfonyl allenols and affords the corresponding structurally unique spiro[5.5]undeca-1,4-dien-3-ones in good yield under mild reaction conditions.

}, issn = {1359-7345}, doi = {10.1039/d0cc01005g}, author = {Ghotekar, Ganesh S. and Shirsath, Sachin R. and Shaikh, Aslam C. and Muthukrishnan, M.} }