Nickel-Catalyzed Regioselective 1,4-Hydroboration of N-Heteroarenes

Tamang, Sem Raj; Singh, Arpita; Unruh, Daniel K.; Findlater, Michael

doi:10.1021/acscatal.8b01166

Cited by 65 publications

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References 64 publications

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“…The difficulty associated with such catalysis to access 1,2-DHQs is control of chemoselectivity and regioselectivity since these reactions always suffer from over-reduction of the more reactive DHQs to THQs 16,36 . The breakthrough in this field was catalytic hydrosilylation and hydroboration of quinolines to the N-silylated or N-borylated 1,2-DHQs [37][38][39][40][41][42][43][44] respectively, using transition metal catalysts or metalfree organocatalysts 45,46 . Deprotection of the silyl or boryl groups of the N-protected DHQs can provide an alternative route to 1,2-DHQs, however, such an N-protection/hydrolysis strategy encounter issues related to functional group compatibility and the complicated purification procedures 39 , which limits the expansion of 1,2-DHQ chemistry.…”

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confidence: 99%

Controlled partial transfer hydrogenation of quinolines by cobalt-amido cooperative catalysis

et al. 2020

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Catalytic hydrogenation or transfer hydrogenation of quinolines was thought to be a direct strategy to access dihydroquinolines. However, the challenge is to control the chemoselectivity and regioselectivity. Here we report an efficient partial transfer hydrogenation system operated by a cobalt-amido cooperative catalyst, which converts quinolines to 1,2-dihydroquinolines by the reaction with H 3 N•BH 3 at room temperature. This methodology enables the large scale synthesis of many 1,2-dihydroquinolines with a broad range of functional groups. Mechanistic studies demonstrate that the reduction of quinoline is controlled precisely by cobalt-amido cooperation to operate dihydrogen transfer from H 3 N•BH 3 to the N=C bond of the substrates.

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Controlled partial transfer hydrogenation of quinolines by cobalt-amido cooperative catalysis

et al. 2020

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“…Most importantly, catalyzed reactions give a measure of control over regioselectivity, enantioselectivity, and chemoselectivity [46,47,48]. Our efforts in hydroboration chemistry employing base metals (Fe, Co, and Ni) have explored the reduction of carbonyls [49], Markovnikov selective functionalization of alkenes [50] and regioselective dearomatization of N -heteroarenes [51].…”

Section: Hydroborationmentioning

confidence: 99%

“…In a related transformation, the dearomatization of N -heteroarenes to afford dihydropyridines (DHPs) is an important transformation as DHPs are the backbones of various pharmaceutically relevant molecules [110,111]. We recently disclosed the first example of nickel-catalyzed 1,4 regioselective dearomatization of N -heteroarenes [51]. This system complements the iron-catalyzed 1,2 regioselective dearomatization of N -heteroarenes reported by Wang and co-workers [68] (Scheme 4).…”

Section: Nickel-catalyzed Hydroboration Of N-heteroarenesmentioning

confidence: 99%

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Emergence and Applications of Base Metals (Fe, Co, and Ni) in Hydroboration and Hydrosilylation

Tamang

Findlater

2019

Molecules

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Base metal catalysis offers an alternative to reactions, which were once dominated by precious metals in hydrofunctionalization reactions. This review article details the development of some base metals (Fe, Co, and Ni) in the hydroboration and hydrosilylation reactions concomitant with a brief overview of recent advances in the field. Applications of both commercially available metal salts and well-defined metal complexes in catalysis and opportunities to further advance the field is discussed as well.

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“…This catalyst showed high reactivity but poor selectivity as the reaction proceeded with almost equal efficiency for ketones, aldehydes, and imines. Recently, a couple of reports have also been published employing nickel for hydroboration of carbon dioxide and N‐heteroarenes …”

Section: Introductionmentioning

confidence: 99%

Nickel(II) Catalyzed Hydroboration: A Route to Selective Reduction of Aldehydes and N‐Allylimines

Hossain

Schmidt

2020

Eur J Inorg Chem

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A cationic [(iminophosphine)nickel(allyl)] + complex was found to be sufficiently electrophilic to activate aldehydes and N-allylimines to undergo hydroboration with pinacolborane (HBpin) under mild reaction conditions. The catalyst displayed excellent selectivity toward aldehydes in the presence of ketones. A wide variety of functional groups were tolerated, includ- [a] I. 1877 ing halogens, NO 2 , CN, OMe, and alkenes for both aldehydes and imines. Electron-rich substrates were found to be significantly more reactive than their electron poor counterparts, a feature that was correlated to their enhanced ability to coordinate to the Lewis acidic nickel center. [40] Colorless liquid (60 mg, 81 % isolated yield). 1 H NMR (600 MHz, CDCl 3 ): δ = 7. 33-7.30 (m, 4H), 7.25-7.22 (m, 1H), 5.92 (ddt, 3 J HH = 17.2, 3 J HH = 10.2, 3 J HH = 6.0 Hz, 1H), 5.19 (dq, 3 J HH = 17.2, 4 J HH = 2 J HH = 1.5 Hz, 1H), 5.10 (dq, 3 J HH = 10.2, 4 J HH = 2 J HH = 1.5 Hz, 1H), 3.78 (s, 2H), 3.27 (dt, 3 J HH = 6.0, 4 J HH = 1.5 Hz, 2H), 1.47 (br s, 1H). 13 C{ 1 H} NMR (151 MHz, CDCl 3 ): δ = 140. 3, 136.9, 128.5, 128.3, 127.1, 116.1, 53.4, 51.9. [30a] Colorless liquid (74 mg, 92 % isolated yield). 1 H NMR (600 MHz, CDCl 3 ): δ = 7.22 (d, 3 J HH = 7.9 Hz, 2H), 7.15 (d, 3 J HH = 7.9 Hz, 2H), 5.94 (ddt, 3 J HH = 17.2, 3 J HH = 10.2, 3 J HH = 6.0 Hz, 1H), 5.20 (dq, 3 J HH = 17.2, 4 J HH = 2 J HH = 1.6 Hz, 1H), 5.12 (dq, 3 J HH = 10.2, 4 J HH = 2 J HH = 1.6 Hz, 1H), 3.76 (s, 2H), 3.28 (dt, 3 J HH = 6.0, 4 J HH = 1.6 Hz, 2H), 2.35 (s, 3H), 1.52 (br s, [41] Colorless liquid (81 mg, 91 % isolated yield). 1 H NMR (600 MHz, CDCl 3 ): δ = 7.24 (d, 3 J HH = 8.3 Hz, 2H), 6.86 (d, 3 J HH = 8.3 Hz, 2H), 5.93 (ddt, 3 J HH = 17.3, 3 J HH = 10.4, 3 J HH = 6.0 Hz, 1H), 5.19 (dq, 3 J HH = 17.3, 4 J HH = 2 J HH = 1.6 Hz, 1H), 5.11 (dq, 3 J HH = 10.4, 4 J HH = 2 J HH = 1.6 Hz, 1H), 3.79 (s, 3H), 3.73 (s, 2H), 3.26 (dt, 3 J HH = 6.0, 4 J HH = 1.6 Hz, 2H), 1.45 (br s, 1H). 13 C{ 1 H} NMR (151 MHz, CDCl 3 ): δ = 158. 7, 136.9, 132.5, 129.5, 116.1, 113.8, 55.4, 52.8, 51.8. N-Benzylprop-2-en-1-amine (2b): N-(4-Methylbenzyl)prop-2-en-1-amine (2c): N-(4-Methoxybenzyl)prop-2-en-1-amine (2d): N-(4-N,N-Dimethylaminobenzyl)prop-2-en-1-amine(2e): [30a] Pale yellow liquid (87 mg, 91 % isolated yield). 1 H NMR (600 MHz, CDCl 3 ): δ = 7.20 (d, 3 J HH = 8.6 Hz, 2H), 6.72 (d, 3 J HH = 8.6 Hz, 2H), 5.94 (ddt, 3 J HH = 16.8, 3 J HH = 10.1, 3 J HH = 6.1 Hz, 1H), 5.19 (dq, 3 J HH = 16.8, 4 J HH = 2 J HH = 1.6 Hz, 1H), 5.10 (dq, 3 J HH = 10.1, 4 J HH = 2 J HH = 1.6 Hz, 1H), 3.70 (s, 2H), 3.27 (dt, 3 J HH = 6.1, 4 J HH = 1.6 Hz, 2H), 2.94 (s, 6H), 1.38 (br s, 1H). 13 C{ 1 H} NMR (151 MHz, CDCl 3 ): δ = 149.9, 136.9, 129.2, 128.2, 115.9, 112.7, 52.8, 51.7, 40.8. N-(4-Fluorobenzyl)prop-2-en-1-amine (2f):[30a] Colorless liquid (71 mg, 86 % isolated yield). 1 H NMR (600 MHz, CDCl 3 ): δ = 7.32-7.27 (m, 2H), 7.04-6.98 (m, 2H), 5.92 (ddt, 3 J HH = 17.1, 3 J HH = 10.2, 3 J HH = 5.9 Hz, 1H), 5.19 (dq, 3 J HH = 17.1, 4 J HH = 2 J HH = 1.4 Hz, 1H), 5.12 (dq, 3 J HH = 10.2, 4 J HH = 2...

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Nickel-Catalyzed Regioselective 1,4-Hydroboration of N-Heteroarenes

Cited by 65 publications

References 64 publications

Controlled partial transfer hydrogenation of quinolines by cobalt-amido cooperative catalysis

Controlled partial transfer hydrogenation of quinolines by cobalt-amido cooperative catalysis

Emergence and Applications of Base Metals (Fe, Co, and Ni) in Hydroboration and Hydrosilylation

Nickel(II) Catalyzed Hydroboration: A Route to Selective Reduction of Aldehydes and N‐Allylimines

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