Acceptorless Photocatalytic Dehydrogenation for Alcohol Decarbonylation and Imine Synthesis

Ho, Hung‐An; Manna, Kuntal; Sadow, Aaron D.

doi:10.1002/anie.201203556

Cited by 91 publications

(44 citation statements)

References 51 publications

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“…The IR spectrum showed a strong absorbance at 1955 cm -1 , proving that the CO ligand was still coordinated. To obtain more information, the newly observed species was labeled with [ 13 C]CO from α-[ 13 C]-benzyl alcohol, which afforded a double doublet in the 13 C NMR spectrum at 167.4 ppm and changed the two singlets in the 31 P NMR spectrum into two doublets with couplings of 3.5 and 14.3 Hz, respectively. The disappearance of the C-P trans-coupling and the P-P cis-coupling from 1, indicates that one of the phosphines has dissociated.…”

Section: The Effect Of Licl and H 2 Omentioning

confidence: 99%

Experimental and Theoretical Mechanistic Investigation of the Iridium-Catalyzed Dehydrogenative Decarbonylation of Primary Alcohols

et al. 2015

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ABSTRACT:The mechanism for the iridium-BINAP catalyzed dehydrogenative decarbonylation of primary alcohols with the liberation of molecular hydrogen and carbon monoxide was studied experimentally and computationally. The reaction takes place by tandem catalysis through two catalytic cycles involving dehydrogenation of the alcohol and decarbonylation of the resulting aldehyde. The square planar complex IrCl(CO)(rac-BINAP) was isolated from the reaction between [Ir(cod)Cl] 2 , rac-BINAP and benzyl alcohol. The complex was catalytically active and applied in the study of the individual steps in the catalytic cycles. One carbon monoxide ligand was shown to remain coordinated to iridium throughout the reaction and release of carbon monoxide was suggested to occur from a dicarbonyl complex. IrH 2 Cl(CO)(rac-BINAP) was also synthesized and detected in the dehydrogenation of benzyl alcohol. In the same experiment, IrHCl 2 (CO)(rac-BINAP) was detected from the release of HCl in the dehydrogenation and subsequent reaction with IrCl(CO)(rac-BINAP). This indicated a substitution of chloride with the alcohol to form a square planar iridium alkoxo complex that could undergo a β-hydride elimination. A KIE of 1.0 was determined for the decarbonylation and 1.42 for the overall reaction. Electron rich benzyl alcohols were converted faster than electron poor alcohols, but no electronic effect was found when comparing aldehydes of different electronic character. The lack of electronic and kinetic isotope effects implies a rate determining phosphine dissociation for the decarbonylation of aldehydes.

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Section: The Effect Of Licl and H 2 Omentioning

confidence: 99%

Experimental and Theoretical Mechanistic Investigation of the Iridium-Catalyzed Dehydrogenative Decarbonylation of Primary Alcohols

et al. 2015

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“…[6][7][8] For instance, Zhao et al reported the photocatalytic oxidation of aromatic amines to corresponding imines using TiO 2 as the photocatalyst. [10] Lin et al found that some doped metal-organic frameworks showed photocatalytic activity for the oxidation. Therefore, the development of visible-light-driven catalysts for aerobic oxidation of amines remains a challenge.…”

Section: Introductionmentioning

confidence: 99%

Visible light-induced selective photocatalytic aerobic oxidation of amines into imines on Cu/graphene

Zhai

Guo

Jin

et al. 2015

Catal. Sci. Technol.

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Graphene can stabilize metallic copper nanoparticles and enable them to exhibit excellent photocatalytic activity for aerobic oxidation of various primary and secondary amines into corresponding imines. The copper nanoparticles stabilized on graphene absorb the energy of visible light via the localized surface plasmon resonance, and produce energetic hot electrons that activate the reactants adsorbed on the surface of copper nanoparticles. The formation of imines involves a selective oxygenation of amines to aldehydes and a subsequent condensation with amines to form imines.

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“…Among the mechanistic scenarios considered for the observed epimerization process, a dehydroamination–hydroamination pathway seemed most plausible and was supported by the careful isolation of a dehydroamination intermediate ( Boc‐18 b , Scheme 3 a‐iii). Finally, based on previously reported examples,– we also considered the possibility of a dehydroxymethylation reaction to access deoxyquinine ( 18 ) from primary alcohol 17 directly (Scheme b). In this context, while the rhodium catalytic conditions recently disclosed by Dong and co‐workers were ineffective for model substrate 17 b , preliminary studies demonstrated Pd II catalysis under conditions reported by Maiti and co‐workers could afford product 17 c (43 %, unoptimized) with its newly formed olefin as a useful diversity‐enabling handle.…”

Section: Figurementioning

confidence: 99%

A Local‐Desymmetrization‐Based Divergent Synthesis of Quinine and Quinidine

Lee

Chen

2018

Angew Chem Int Ed

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Herein we report a novel synthetic entry to the legendary quinuclidine natural products quinine and quinidine. The developed strategy is based on the use of a symmetrical and nonstereogenic precursor to access quinine and quinidine through a “local‐desymmetrization” approach, in stark contrast conceptually to the preparation of stereodefined disubstituted piperidines (or their acyclic precursors) as featured in all past syntheses. The developed strategy also provided quinine and quinidine derivatives that could not be readily obtained through previous total syntheses or by modification of the naturally occurring substances.

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Acceptorless Photocatalytic Dehydrogenation for Alcohol Decarbonylation and Imine Synthesis

Cited by 91 publications

References 51 publications

Experimental and Theoretical Mechanistic Investigation of the Iridium-Catalyzed Dehydrogenative Decarbonylation of Primary Alcohols

Experimental and Theoretical Mechanistic Investigation of the Iridium-Catalyzed Dehydrogenative Decarbonylation of Primary Alcohols

Visible light-induced selective photocatalytic aerobic oxidation of amines into imines on Cu/graphene

A Local‐Desymmetrization‐Based Divergent Synthesis of Quinine and Quinidine

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