@article {44627, title = {Copper- and phosphine-free nickel(II)-catalyzed method for C-H bond alkynylation of benzothiazoles and related azoles}, journal = {Asian Journal of Organic Chemistry}, volume = {7}, year = {2018}, month = {JUL}, pages = {1390-1395}, abstract = {

A phosphine-free nickel(II)-catalyzed method for the C(2)-H bond alkynylation of (benzo)thiazoles, (benz)imidazoles, and oxazoles is described. Well-defined and air-stable (Phen)NiCl2 catalyst efficiently catalyzes the coupling of diverse azoles with alkynyl bromides without the use of a copper co-catalyst, and the method tolerates synthetically important functional groups. Preliminary mechanistic studies on this Ni-II-catalyzed alkynylation emphasize the homogeneous nature of the catalyst, and rule out a radical manifold for the reaction. The synthetic utility of this Ni-catalyzed method is demonstrated by further functionalizing the alkynylated benzothiazoles to 3-methyl-2-(alkynyl)benzo[d]thiazolium salts that are known DNA cleaving agents.

}, keywords = {alkynylation, azoles, C-H activation, heterocycles, Nickel}, issn = {2193-5807}, doi = {10.1002/ajoc.201800243}, author = {Patel, Ulhas N. and Punji, Benudhar} } @article {46673, title = {Expeditious and solvent-free nickel-catalyzed c-h arylation of arenes and indoles (vol 10, pg 2242, 2017)}, journal = {ChemSusChem}, volume = {13}, year = {2020}, month = {NOV }, pages = {5771}, type = {Correction}, keywords = {Arylation, C-H activation, heterocycles, Homogeneous catalysis, Nickel}, issn = {1864-5631}, doi = {10.1002/cssc.202002313, Early Access Date = OCT 2020}, author = {Jagtap, Rahul A. and Soni, Vineeta and Punji, Benudhar} } @article {49125, title = {Advances in the iron-catalyzed direct functionalizations of heterocycles}, journal = {Synlett}, volume = {34}, year = {2023}, month = {APR}, pages = {683-697}, type = {Article}, abstract = {

Direct functionalization of heterocycles is an advanced strategy for diversifying privileged and biorelevant heterocycle-containing molecules. Particularly, use of the most abundant transition metal, iron, as a catalyst makes this process highly cost-effective and sustainable. Recently, some progress has been realized towards the direct functionalization of heterocycles under iron catalysis. Herein, we present the developments in the C-H bond functionalizations and related reactions of various heterocycles by abundant iron salts. This Synpacts is categorized into different sections based on heterocycles being functionalized, and each section is discussed based on the type of reaction catalyzed by iron. 1 Introduction 2 Functionalization of Indoles 2.1 Alkylation 2.2 Alkenylation 2.3 Other Reactions 3 Oxindoles and isatins 3.1 C-C Bond Formation 3.2 C-Heteroatom Bond Formation 4 Pyridines and Furans 5 Functionalization of Azoles 6 Summary and Outlook

}, keywords = {Alkylation, azoles, C-H functionalization, heterocycles, indoles, iron, Mechanism}, issn = {0936-5214}, doi = {10.1055/a-1890-8503}, author = {Pradhan, Chandini and Punji, Benudhar} } @article {49190, title = {Chemodivergent dehydrogenative coupling of alcohols by 3d metal catalysts}, journal = {ChemCatChem}, volume = {16}, year = {2024}, month = {JUN }, type = {Article}, abstract = {

Chemodivergent synthesis by transition metal catalysts is a straightforward and sustainable approach to achieving valuable organic compounds. Especially, the chemodivergent dehydrogenative couplings of alcohols with organic motifs to develop various saturated and unsaturated compounds are highly environmentally benign due to the reduced waste generation. In this concept review, we presented the 3d transition metal (Mn, Fe, Co, and Ni)-catalyzed chemodivergent synthesis of imines and amines, saturated and unsaturated carbonyl/alcohol compounds, saturated and unsaturated nitriles, N-heterocycles, and N-/C-alkylated indoles. The discussed reaction commanded two or three different products with high chemoselectivity by changing specific reaction parameters, but keeping the catalyst unchanged. Generally, the acceptorless dehydrogenative coupling (ADC) provides unsaturated moieties, whereas the borrowing-hydrogen (BH) process results in saturated compounds. Text for Table of Contents: An overview of the chemodivergent dehydrogenative coupling of alcohols by the Earth-abundant transition metal catalysts is discussed. image

}, keywords = {3d metals, Alcohols, chemodivergent, dehydrogenative coupling, heterocycles}, issn = {1867-3880}, doi = {10.1002/cctc.202301558}, author = {Bansal, Sadhna and Punji, Benudhar} }