@article {46311,
	title = {Nickel-catalyzed C-H alkylation of indoles with unactivated alkyl chlorides: evidence of a Ni(i)/Ni(iii) pathway},
	journal = {Chemical Science},
	volume = {10},
	year = {2019},
	month = {NOV},
	pages = {9493-9500},
	type = {Article},
	abstract = {<p>A mild and efficient nickel-catalyzed method for the coupling of unactivated primary and secondary alkyl chlorides with the C-H bond of indoles and pyrroles is described which demonstrates a high level of chemo and regioselectivity. The reaction tolerates numerous functionalities, such as halide, alkenyl, alkynyl, ether, thioether, furanyl, pyrrolyl, indolyl and carbazolyl groups including acyclic and cyclic alkyls under the reaction conditions. Mechanistic investigation highlights that the alkylation proceeds through a single-electron transfer (SET) process with Ni(i)-species being the active catalyst. Overall, the alkylation follows a Ni(i)/Ni(iii) pathway involving the rate-influencing two-step single-electron oxidative addition of alkyl chlorides.</p>
},
	issn = {2041-6520},
	doi = {10.1039/c9sc01446b},
	author = {Pandey, Dilip K. and Ankade, Shidheshwar B. and Ali, Abad and Vinod, C. P. and Punji, Benudhar}
}
@article {47635,
	title = {Achiral and chiral NNN-pincer nickel complexes with oxazolinyl backbones: application in transfer hydrogenation of ketones},
	journal = {New Journal of Chemistry},
	volume = {45},
	year = {2021},
	month = {JUL},
	pages = {11927-11936},
	type = {Article},
	abstract = {We describe the synthesis of new NNN-oxazolinyl-pincer nickel complexes and their application in the transfer hydrogenation of ketones. Achiral NNN-ligands, R {\textquoteleft}(2)-oxazolinyl-2-C6H4-NH-C(O)CH2NEt2 [((R {\textquoteleft} 2-OxNNNEt2))-H; R{\textquoteright} = H (3a), R {\textquoteleft} = Me (3b)], and chiral ligands, (R)-R {\textquoteleft}-oxazolinyl-2-C6H4-NH-C(O)CH2NEt2 [(R)-((R {\textquoteleft}-OxNNNEt2))-H; R {\textquoteleft} = Ph (3c), R {\textquoteleft} = CH2Ph (3d), R {\textquoteleft} = Pr-i (3e), R {\textquoteleft} = (CH2Pr)-Pr-i (3f)], were efficiently synthesized. Treatment of these ligands with (DME)NiCl2 afforded the desired amido-pincer nickel complexes, ((R {\textquoteleft} 2-OxNNNEt2))NiCl [R {\textquoteleft} = H (4a), R {\textquoteleft} = Me (4b)] and ((R {\textquoteleft}-OxNNNEt2))NiCl [R {\textquoteleft} = Ph (4c), R {\textquoteleft} = CH2Ph (4d), R {\textquoteleft} = Pr-i (4e), R {\textquoteleft} = (CH2Pr)-Pr-i (4f)], in good yields. All the ligand precursors and nickel complexes were thoroughly characterized by various analytical techniques. The molecular structures of 4a, 4d and 4f were established by X-ray crystallography. The developed nickel complexes were found to be efficient catalysts for the transfer hydrogenation of ketones using (PrOH)-Pr-i as a viable hydrogen source. Enantioselectivity in hydrogenation was not observed with the developed chiral catalysts.},
	issn = {1144-0546},
	doi = {10.1039/d1nj01698a},
	author = {Jagtap, Rahul A. and Ankade, Shidheshwar B. and Gonnade, Rajesh G. and Punji, Benudhar}
}
@article {47638,
	title = {Ni(II)-catalyzed intramolecular C-H/C-H oxidative coupling: an efficient route to functionalized cycloindolones and indenoindolones},
	journal = {ACS Catalysis},
	volume = {11},
	year = {2021},
	month = {OCT },
	pages = {12384-12393},
	type = {Article},
	abstract = {Nickel(II)-catalyzed intramolecular C(sp(2))-H/C(sp(3))-H and C(sp(2))-H/C(sp(2))-H oxidative couplings in indoles are achieved via chelation assistance. These reactions provide access to biologically relevant five- and six-membered substituted cyclopentaindolones, carbazolones, and indenoindolones in high yields and good chemoselectivity employing an air-stable and defined nickel catalyst, (bpy)Ni(OAc)(2). The oxidative cyclizations proceeded either through a six-membered or an unconventional seven-membered nickelacycle. An extensive mechanistic investigation by experiments and theoretical calculations revealed a facile indole{\textquoteright}s C(2)-H nickelation and a rate-limiting reductive elimination process. This intramolecular oxidative cyclization operates via a probable Ni(II)/Ni(III) pathway involving single-electron oxidation of nickel without the participation of a carbon-based radical.},
	keywords = {C-H activation, cycloindolones, indenoindolones, indoles, Mechanism, Nickel, oxidative coupling},
	issn = {2155-5435},
	doi = {10.1021/acscatal.1c03314},
	author = {Ankade, Shidheshwar B. and Samal, Pragnya Paramita and Soni, Vineeta and Gonnade, Rajesh G. and Krishnamurty, Sailaja and Punji, Benudhar}
}
@article {47036,
	title = {Unactivated alkyl halides in transition-metal-catalyzed C-H bond alkylation},
	journal = {ACS Catalysis},
	volume = {11},
	year = {2021},
	month = {MAR },
	pages = {3268-3292},
	type = {Review},
	abstract = {<p>Alkylation represents an important organic transformation in molecular science to develop privileged alkylated arenes and heteroarenes. Especially, the direct C-H bond alkylation using unactivated alkyl halides is a straightforward and attractive approach from both the step-economy and chemoselectivity perspectives. Substantial progress has been made in the direct alkylation using primary, secondary, and tertiary alkyl halides along with the methylation and fluoroalkylation. This Review broadly summarizes the transition-metal-catalyzed alkylations of C-H bonds on various arenes and heteroarenes with unactivated alkyl halides until October 2020. On the basis of the substrates utilized for alkylation, the Review is divided into two major sections: alkylation of arenes and alkylation of heteroarenes.</p>
},
	keywords = {(hetero)arenes, Alkylation, C-H activation, transition metals, unactivated alkyl halides},
	issn = {2155-5435},
	doi = {10.1021/acscatal.0c05580},
	author = {Ankade, Shidheshwar B. and Shabade, Anand B. and Soni, Vineeta and Punji, Benudhar}
}
