@article { ISI:000364933100004, title = {Reversed reactivity of anilines with alkynes in the rhodium-catalysed C-H activation/carbonylation tandem}, journal = {Nature Communications}, volume = {6}, year = {2015}, month = {OCT}, pages = {Article Number: 8591}, publisher = {NATURE PUBLISHING GROUP}, address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND}, abstract = {

Development of multicatalytic approach consisting of two or more mechanistically distinct catalytic steps using a single-site catalyst for rapid and straightforward access of structurally complex molecules under eco-benign conditions has significance in contemporary science. We have developed herein a rhodium-catalysed C-H activation strategy which uses an unprotected anilines and an electron-deficient alkynes to C-C bonded products as a potential intermediate in contrast to the archetypical C-N bonded products with high levels of regioselectivity. This is followed by carbonylation of C-H bond activated intermediate and subsequent annulation into quinolines has been described. This rhodium-catalysed auto-tandem reaction operates under mild, environmentally benign conditions using water as the solvent and CO surrogates as the carbonyl source with the concomitant generation of hydrogen gas. The strategy may facilitate the development of new synthetic protocols for the efficient and sustainable production of chemicals in an atom-economic way from simple, abundant starting materials.

}, issn = {2041-1723}, doi = {10.1038/ncomms9591}, author = {Midya, Siba Prasad and Sahoo, Manoj Kumar and Landge, Vinod Gokulkrishna and Rajamohanan, P. R. and Balaraman, Ekambaram} } @article { ISI:000363389400005, title = {Transition-metal-catalyzed hydrogen-transfer annulations: access to heterocyclic scaffolds}, journal = {Angewandte Chemie-International Edition}, volume = {54}, number = {38}, year = {2015}, month = {SEP}, pages = {11022-11034}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {

The ability of hydrogen-transfer transition-metal catalysts, which enable increasingly rapid access to important structural scaffolds from simple starting materials, has led to a plethora of research efforts on the construction of heterocyclic scaffolds. Transition-metal-catalyzed hydrogen-transfer annulations are environmentally benign and highly atom-economical as they release of water and hydrogen as by-product and utilize renewable feedstock alcohols as starting materials. Recent advances in this field with respect to the annulations of alcohols with various nucleophilic partners, thus leading to the formation of heterocyclic scaffolds, are highlighted herein.

}, issn = {1433-7851}, doi = {10.1002/anie.201503247}, author = {Nandakumar, Avanashiappan and Midya, Siba Prasad and Landge, Vinod Gokulkrishna and Balaraman, Ekambaram} } @article {42699, title = {Well-defined palladium(II) complexes for ligand enabled C(sp3)-alkynylation}, journal = {Dalton Transactions}, volume = {44}, year = {2015}, month = {JUL}, pages = {15382-15386}, abstract = {

The first example of ligand-enabled C(sp3)-alkynylation of 8-methylquinoline is reported. The reaction is catalysed by well-defined Pd(II) complexes. The present C(sp3)-alkynylation has a broad substrate scope as well as functional group tolerance and proceeds efficiently under mild conditions.

}, doi = {10.1039/C5DT02772A}, author = {Landge, Vinod Gokulkrishna and Sahoo, Manoj Kumar and Midya, Siba Prasad and Jaiswal, Garima and Balaraman, Ekambaram} } @article {42695, title = {Cobalt-catalyzed bis-alkynylation of amides via double C{\textendash}H bond activation}, journal = {Organic Letters}, volume = {18}, year = {2016}, month = {FEB}, pages = {812{\textendash}815}, abstract = {

The first example of cobalt-catalyzed selective bis-alkynylation of amides via double C{\textendash}H bond activation with the directing assistance of a removable bidentate auxiliary is reported. The developed alkynylation strategy is simple, efficient, and tolerant of various functional groups including ether, amine, halides, and heterocyclic motifs. The reaction can be scaled up under mild conditions.

}, doi = {10.1021/acs.orglett.6b00095}, author = {Landge, Vinod Gokulkrishna and Jaiswal, Garima and Balaraman, Ekambaram} } @article {42693, title = {Expedient cobalt-catalyzed C{\textendash}H alkynylation of (enantiopure) benzylamines}, journal = {Organic Letters}, volume = {18}, year = {2016}, month = {OCT}, pages = {5252-5255}, abstract = {

A unified strategy for cobalt-catalyzed ortho-C-H bond alkynylation of benzylamines is reported. Simple, commercially available CoBr2 was used as a cobalt source. The developed alkynylation strategy is robust and efficient and has a broad substrate scope including 1 degrees, 2 degrees, and 3 degrees benzylamines. The mechanistic study shows that C-H bond cleavage is reversible, and the kinetic study illustrates that the rate of reaction depends solely on the catalyst.

}, keywords = {Terminal Alkynes; Bond Activation; Directed Functionalization;Aminoquinoline Benzamides; Ortho-C(Sp(2))-H Bonds; Mechanistic Insights; Selective Access; Carbon-Hydrogen; Nickel; Annulation}, doi = {10.1021/acs.orglett.6b02549}, author = {Landge, Vinod Gokulkrishna and Midya, Siba Prasad and Rana, Jagannath and Shinde, Dinesh R. and Balaraman, Ekambaram} } @article {42696, title = {Nickel-catalyzed direct alkynylation of C(sp2)-H bonds of amides: an {\textquotedblleft}inverse sonogashira strategy{\textquotedblright} to ortho-alkynylbenzoic acids. just accepted}, journal = {Catalysis Science \& Technology}, volume = {6}, year = {2016}, month = {OCT}, pages = {1946-1951}, abstract = {

Nickel-catalyzed direct alkynylation of C(sp2){\textendash}H bonds of amides using commercially available, inexpensive 8-aminoquinoline as a removable bidentate directing group is described. The present ortho-alkynylation has a broad substrate scope, functional group tolerance and high regiocontrol, and can be scaled up. The efficiency and selectivity of this strategy provide sustainable routes to a diverse array of ortho-alkynylbenzoic acids under Ni(II)-catalyzed conditions.

}, doi = {10.1039/C5CY01299F}, author = {Landge, Vinod Gokulkrishna and Shewale, Chinmay H. and Jaiswal, Garima and Sahoo, Manoj Kumar and Midya, Siba Prasad and Balaraman, Ekambaram} } @article {42694, title = {Sustainable Iron-catalyzed direct imine formation by acceptorless dehydrogenative coupling of alcohols with amines}, journal = {Green Chemistry}, volume = {18}, year = {2016}, month = {MAY}, pages = {3232-3238}, abstract = {

The Acceptorless Dehydrogenative Coupling (ADC) of alcohols with amines is reported using a heterogeneous Fe-catalyst. The reaction operates under mild conditions with the liberation of dihydrogen and water as the byproducts. The developed ADC strategy is simple, efficient, exhibits wide functional group tolerance and can be scaled up. The present catalytic approach possesses a dual role; acting as a catalyst as well as being magnetically separable. The sustainable reuse of a heterogeneous iron catalyst is also shown.

}, doi = {10.1039/C6GC00565A}, author = {Jaiswal, Garima and Landge, Vinod Gokulkrishna and Jagadeesan, Dinesh and Balaraman, Ekambaram} }