02123nas a2200265 4500008004100000022001400041245013800055210006900193260000900262300001400271490000700285520121800292653002001510653001501530653001901545653002501564653001401589653000901603100002201612700002901634700001801663700002601681700002001707856013001727 2020 eng d a2155-543500aIron-catalyzed C(sp(2))-H alkylation of indolines and benzo[h]quinoline with unactivated alkyl chlorides through chelation assistance0 aIroncatalyzed Csp2H alkylation of indolines and benzohquinoline  cJUL  a7312-73210 v103 a

Regioselective C-H bond alkylation of indolines and benzo[h]quinoline with a wide range of unactivated and highly demanded primary and secondary alkyl chlorides is accomplished using a low-cost iron catalyst. This reaction tolerates diverse functionalities, such as C(sp(2))-Cl, fluoro, alkenyl, silyl, ether, thioether, pyrrolyl, and carbazolyl groups including cyclic and acyclic alkyls as well as alkyl-bearing fatty-alcohol and polycyclic-steroid moieties. The demonstrated iron-catalyzed protocol proceeded via either a five-membered or a six-membered metallacycle. Intriguingly, the C-7-alkylated indolines can be readily functionalized into free-NH indolines/indoles and tryptamine derivatives. A detailed mechanistic investigation highlights the participation of an active Fe(I) catalyst and the involvement of a halogen-atom transfer process via a single-electron-based mechanism. Deuterium labeling and kinetics analysis indicate that the C-H metalation of indoline is the probable turnover-limiting step. Overall, the experimental and theoretical studies supported an Fe(I)/Fe(III) pathway for the alkylation reaction comprising the two-step, one-electron oxidative addition of alkyl chloride.

10aalkyl chlorides10aAlkylation10aC-H activation10achelation assistance10aindolines10airon1 aJagtap, Rahul, A.1 aSamal, Pragnya, Paramita1 aVinod, C., P.1 aKrishnamurty, Sailaja1 aPunji, Benudhar uhttps://library.ncl.res.in/content/iron-catalyzed-csp2-h-alkylation-indolines-and-benzohquinoline-unactivated-alkyl-chlorides02048nas a2200229 4500008004100000022001400041245010800055210006900163260000900232300001400241490000700255520125900262653002101521653001001542653002201552100002201574700002201596700002901618700002601647700002001673856012501693 2023 eng d a1463-926200aIron-catalyzed regioselective C-H alkylation of indoles: an additive-free approach in renewable solvent0 aIroncatalyzed regioselective CH alkylation of indoles an additiv cNOV  a9733-97430 v253 a

Alkylated indoles are important motifs in various biologically active molecules and drug candidates. Herein, we report a mild and efficient iron-catalyzed protocol for synthesizing alkylated indoles via C-H bond alkylation of indoles with unactivated alkenes, demonstrating a high level of regioselectivity. The reaction occurs under additive-free, solvent-free (or trace green solvent, 2-MeTHF) and less energy-intensive conditions using a sustainable metal catalyst and provides easy access to privileged alkylated indoles with anti-Markovnikov selectivity. Alkylation is compatible with important functionalities, such as fluoro, chloro, trifluoromethyl, alkenyl, ether, thioether, silyl, and siloxane, including heteroaryl, pyridinyl, carbazolyl, and indolyl moieties (45 examples, up to 96% yield). The developed protocol is very simple, straightforward, and fully accords with the principles of green chemistry. A detailed mechanistic investigation manifests the facile indole's C-H activation at the Fe(0) center, reversible 1,2-insertion of the alkene into the Fe-H bond of a metallacycle, and a turnover-limiting reductive elimination. Alkylated indoles are important motifs in various biologically active molecules and drug candidates.

10aAromatic Ketones10aGreen10aorganic synthesis1 aPradhan, Chandini1 aJagtap, Rahul, A.1 aSamal, Pragnya, Paramita1 aKrishnamurty, Sailaja1 aPunji, Benudhar uhttps://library.ncl.res.in/content/iron-catalyzed-regioselective-c-h-alkylation-indoles-additive-free-approach-renewable01844nas a2200265 4500008004100000022001400041245012400055210006900179260000900248300001400257490000800271520093200279653001401211653000901225653001101234653002101245653004101266100002801307700002201335700002901357700002401386700002601410700002001436856012201456 2024 eng d a1615-415000aIron-catalyzed C-C and C-N bond-forming tandem amidation offering access to 3-amino-3-aminomethyl-2-oxindole frameworks0 aIroncatalyzed CC and CN bondforming tandem amidation offering ac cJUN  a2801-28100 v3663 a

An iron-catalyzed protocol for the synthesis of 3-amino-3-aminomethyl-2-oxindole heterocyclic structures is disclosed employing isatins and non-nucleophilic N-methoxybenzamides. This reaction class is associated with broad scope and tolerates numerous functionalities, such as fluoro, chloro, bromo, iodo, trifluoromethyl, nitrile, ester, ether, and alkenyl, including heteroaryl - thiophene, benzothiophene, carbazolyl, indolyl, eugenol, and polycyclic cholesterol moieties. Detailed mechanistic investigations reveal that the reaction proceeds via iron-catalyzed N-O bond cleavage in N-methoxybenzamides, generating formaldehyde and benzamide, and through the intermediacy of isatin-ketimines and N-(hydroxymethyl)benzamides. Overall, this amidation reaction involves one C-C and two C-N bond-forming tandem processes, providing a range of beta-amino-aminomethyl-oxindoles (45 examples) in up to 88% yields. image

10abenzamide10airon10aIsatin10atandem amidation10atetrasubstituted carbon stereocenter1 aAnkade, Shidheshwar, B.1 aPradhan, Chandini1 aSamal, Pragnya, Paramita1 aGonnade, Rajesh, G.1 aKrishnamurty, Sailaja1 aPunji, Benudhar uhttps://library.ncl.res.in/content/iron-catalyzed-c-c-and-c-n-bond-forming-tandem-amidation-offering-access-3-amino-3