Ligand design for Rh(<scp>iii</scp>)-catalyzed C–H activation: an unsymmetrical cyclopentadienyl group enables a regioselective synthesis of dihydroisoquinolones

Hyster, Todd K.; Dalton, Derek M.; Rovis, Tomislav

doi:10.1039/c4sc02590c

Cited by 135 publications

(70 citation statements)

References 52 publications

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“…Dihydroisoquinolones have previously been synthesized by Rh(III)-catalyzed annulations of O- pivaloyl or O- Boc benzhydroxamic acids and alkenes, but controlling selectivity is often a challenge, and a mixture of isomers is typically observed. 12 Dihydroisoquinolone 5a was obtained in high yield with the structure confirmed by X-ray crystallographic analysis. This is a different isomer than that obtained by the Rh(III)-catalyzed annulation of O -Boc benzhydroxamic acid and styrene.…”

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confidence: 86%

Rh(III)-Catalyzed Aryl and Alkenyl C–H Bond Addition to Diverse Nitroalkenes

et al. 2016

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The transition metal catalyzed C–H bond addition to nitroalkenes has been developed. Very broad nitroalkene scope was observed for this Rh(III)-catalyzed method, including for aliphatic, aromatic and β,β-disubstituted derivatives. Additionally, various directing groups and both aromatic and alkenyl C–H bonds were effective in this transformation. Representative nitroalkane products were converted to dihydroisoquinolones and dihydropyridones in a single step and in high yield by iron mediated reduction and in situ cyclization. Moreover, preliminary success in enantioselective Rh(III)-catalyzed C–H bond addition to nitroalkenes was achieved as was X-ray structural characterization of a nitronate intermediate.

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confidence: 86%

Rh(III)-Catalyzed Aryl and Alkenyl C–H Bond Addition to Diverse Nitroalkenes

et al. 2016

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“…As can be seen from the Table, replacing the Cp* ligand ( A 1 ) with its more sterically congested tert- butyl-substituted congener ( A 2 ) increases the yield of the 2,3-dihydropyridine product ( 3aa ) from 81% to 91%. Product yield is further enhanced when electron-deficient Cp-ligand A 3 bearing a trifluoromethyl 10b substituent is used. Provided that CsOAc was employed as an additive, product 3aa was isolated in 99% yield when 5 mol % of A 3 was used.…”

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confidence: 99%

Expedient Access to 2,3-Dihydropyridines from Unsaturated Oximes by Rh(III)-Catalyzed C–H Activation

et al. 2015

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α,β-Unsaturated oxime pivalates are proposed to undergo reversible C(sp2)-H insertion with cationic Rh(III) complexes to furnish five-membered metallacycles. In the presence of 1,1-disubstituted olefins, these species participate in irreversible migratory insertion to give, after reductive elimination, 2,3-dihydropyridine products in good yields. Catalytic hydrogenation was then used to convert these molecules into piperidines, which are important structural components of numerous pharmaceuticals.

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“…Recently, the Rovis group creatively designed a bulky di- tert -butyl substituted cyclopentadienyl ligand to enable a regioselective synthesis of dihydroisoquinolones. [53] This Cp ligand significantly improved the regioselectivity for migratory insertion that was obtained when compared to the commonly employed Cp * ligand and other Cp ligands (Table 4). Meanwhile, the regioselectivity for the C(sp 2 )–H activation step decreased when dealing with meta -substituted substrates, which can be explained by the uneven distribution of steric bulk in the Cp 3 ligand.…”

Section: Rhodium Catalysismentioning

confidence: 97%

A Simple and Versatile Amide Directing Group for C−H Functionalizations

et al. 2016

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Achieving selective C–H activation at a single and strategic site in the presence of multiple C–H bonds can provide a powerful and generally useful retrosynthetic disconnection. In this context, the directing group serves as a compass to guide the transition metal to C–H bonds using distance and geometry as powerful recognition parameters to distinguish between proximal and distal C–H bonds. However, the installation and removal of directing groups is a practical drawback. To improve the utility of this approach, one can seek solutions in three directions. First, simplifying the directing group; Second, use of common functional groups or protecting groups as directing groups; Third, attaching the directing group to substrates via a transient covalent bond to render directing groups catalytic. This review describes the rational development of an extremely simple and yet broadly applicable directing group for Pd(II), Rh(III) and Ru(II) catalysts, namely, the N-methoxy amide (CONHOMe). Through collective efforts in the community, a wide range of C–H activation transformations using this type of simple directing groups has been developed.

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Ligand design for Rh(iii)-catalyzed C–H activation: an unsymmetrical cyclopentadienyl group enables a regioselective synthesis of dihydroisoquinolones

Cited by 135 publications

References 52 publications

Rh(III)-Catalyzed Aryl and Alkenyl C–H Bond Addition to Diverse Nitroalkenes

Rh(III)-Catalyzed Aryl and Alkenyl C–H Bond Addition to Diverse Nitroalkenes

Expedient Access to 2,3-Dihydropyridines from Unsaturated Oximes by Rh(III)-Catalyzed C–H Activation

A Simple and Versatile Amide Directing Group for C−H Functionalizations

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