01477nas a2200217 4500008004100000022001400041245010200055210006900157260000800226300001500234490000700249520075700256653001501013653001901028653001301047653001601060653001401076100002401090700002001114856012501134 2022 eng d a1861-472800aManganese-catalyzed C(sp(2))-H alkylation of indolines and arenes with unactivated alkyl bromides0 aManganesecatalyzed Csp2H alkylation of indolines and arenes with cMAY ae2022001030 v173 a

Selective C(sp(2))-H bond alkylation of indoline, carbazole and (2-pyridinyl)arenes with unactivated alkyl bromides is achieved using MnBr2 catalyst in the absence of an external ligand. The alkylation uses a simple LiHMDS base and avoids the necessity of Grignard reagent, unlike other Mn-catalyzed C-H functionalization. This reaction proceeded either through a five- or a less-favored six-membered metallacycle, and tolerated diverse functionalities, including alkenyl, alkynyl, silyl, aryl ether, pyrrolyl, indolyl, carbazolyl and alkyl bearing fatty alcohol and polycyclic-steroid moieties. Alkylation follows a single electron transfer (SET) pathway involving 1e oxidative addition of alkyl bromide and a rate-limiting C-H metalation.

10aAlkylation10aC-H activation10aindoline10aligand-free10amanganese1 aVerma, Suryadev, K.1 aPunji, Benudhar uhttps://library.ncl.res.in/content/manganese-catalyzed-csp2-h-alkylation-indolines-and-arenes-unactivated-alkyl-bromides01592nas a2200217 4500008004100000022001400041245009300055210006900148260000800217490000700225520086500232653002101097653001101118653001801129653001401147653002201161100002501183700002201208700002001230856012401250 2024 eng d a1861-472800aLigand-free MnBr2-catalyzed chemo- and stereoselective hydroboration of terminal alkynes0 aLigandfree MnBr2catalyzed chemo and stereoselective hydroboratio cMAY0 v193 a

Developing simple and benign protocols for synthesizing alkenylboronates is crucial as they are synthetically valuable compounds in various organic transformations. In this work, we report a straightforward ligand-free protocol for synthesizing alkenylboronates via atom-economical hydroboration of alkynes with HBpin catalyzed by a manganese salt. The reaction shows a high level of chemo and regioselectivity for the terminal alkynes and exclusively produces E-selective alkenylboronates. The hydroboration scope is vast, with the resilience of a range of synthetically beneficial functionalities, such as halides, ether, alkenyl, silyl and thiophenyl groups. This reaction proceeds through the involvement of a metal-hydride intermediate. The developed alkenylboronate can be smoothly converted to useful C-C, C-N and C-I bond-forming reactions.

10aalkenylboronates10aalkyne10aHydroboration10amanganese10astereoselectivity1 aPawar, Rameshwar, B.1 aKarmur, Mital, H.1 aPunji, Benudhar uhttps://library.ncl.res.in/content/ligand-free-mnbr2-catalyzed-chemo-and-stereoselective-hydroboration-terminal-alkynes01801nas a2200253 4500008004100000022001400041245012100055210007100176260000800247300001400255490000800269520091600277653001001193653002301203653002101226653002501247653001401272653002901286100002301315700002101338700002401359700002001383856014401403 2024 eng d a1615-415000aManganese-catalyzed chemoselective direct hydrogenation of α,β-epoxy ketones and α-ketoamides at room temperature0 aManganesecatalyzed chemoselective direct hydrogenation of αβepox cAUG a3338-33450 v3663 a

Chemoselective hydrogenation of alpha,beta-epoxy ketones and alpha-ketoamides is achieved at room temperature (25 degrees C) using 2.0 bar H-2 and a pincer-ligated Mn(I) catalyst that provides synthetically valuable alpha-hydroxy epoxides and alpha-hydroxy amides. This protocol applies to a wide range of alkyl- and aryl-substituted alpha,beta-epoxy ketones, including terpenes (alpha-ionone, nootkatone, and R-carvone)- and steroids (testosterone and progesterone)-derived epoxy ketones, and tolerates H-2 sensitive functionalities, such as halides, acetyl, nitrile, nitro, epoxide, alkenyl and alkynyl groups. Additionally, alpha-ketoamides bearing reducible functional groups, including acetyl and diazo benzene, were untouched under this protocol and selectively converted to alpha-hydroxy amides. A preliminary mechanistic study highlighted the metal-ligand cooperative H-2 activation process.

10aalpha10abeta-epoxy ketones10achemoselectivity10adirect hydrogenation10amanganese10aMetal-ligand cooperation1 aShabade, Anand, B.1 aSingh, Rahul, K.1 aGonnade, Rajesh, G.1 aPunji, Benudhar uhttps://library.ncl.res.in/content/manganese-catalyzed-chemoselective-direct-hydrogenation-%CE%B1%CE%B2-epoxy-ketones-and-%CE%B1-ketoamides