Bimetallic Radical Redox-Relay Catalysis for the Isomerization of Epoxides to Allylic Alcohols

Ye, Ke‐Yin; McCallum, Terry; Lin, Song

doi:10.26434/chemrxiv.8178926

Cited by 12 publications

(19 citation statements)

References 21 publications

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“…31 Na2CO3 was barely soluble in the mixed solvent of DMF/MeCN (1:1), explaining its failure in promoting the reaction of [Co III ] with 2 under the static conditions employed for the CV testing. Based on the results of this study and previous work, 31,35 a possible mechanism for the electrocatalytic allylic C-H alkylation reaction was proposed (Fig. 5d).…”

Section: Resultssupporting

confidence: 69%

Dual-functional cobalt catalyst enables electrocatalytic allylic C–H alkylation

Chen

2021

Preprint

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Transition metal-catalyzed allylic substitution reactions of pre-activated allylation agents with nucleophiles are extensively studied synthetic methods that have enjoyed widespread applications in organic synthesis. The direct alkylation of allylic C-H bonds with nucleophiles, which minimizes pre-functionalization and converts inexpensive, abundantly available materials to value-added alkenyl-substituted products, remains challenging. Current methods generally involve C-H activation, require the use of noble-metal catalysts and stoichiometric chemical oxidants, and often show limited scope. Here we report an electrocatalytic allylic C-H alkylation reaction with carbon nucleophiles employing an easily available cobalt-salen complex as the molecular catalyst. These C(sp 3 )-H/C(sp 3 )-H cross-coupling reactions proceed through H2 evolution and require no external chemical oxidants. Importantly, the mild conditions and radical mechanism ensure excellent functional group tolerance and substrate compatibility with both linear and branched terminal alkenes. The synthetic utility of the electrochemical method is highlighted by its scalability (up to 200 mmol scale) and its successful application in the late-stage functionalization of complex structures.

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Section: Resultssupporting

confidence: 69%

Dual-functional cobalt catalyst enables electrocatalytic allylic C–H alkylation

Chen

2021

Preprint

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“…2 While our protocol con- verted 1AL to 2AL, ring opening of a similar cholesterol (R' = Bz) with titanocene furnished a tertiary radical, and the adjacent hydrogen was abstracted by a cobalt catalyst leading to an allylic alcohol. 38 These contrasting results demonstrated that our catalytic protocol is complementary to conventional methods with titanocene.…”

mentioning

confidence: 95%

Reverse Regioselectivity in Reductive Ring Opening of Epoxide Enabled by Zirconocene and Photoredox Catalysis

Yamaguchi¹,

Ota²,

Hirao³

et al. 2021

Preprint

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A ring opening of epoxide with zirconocene and photoredox catalysis has been developed. Compared to the ring opening methods with titanocene, the present protocol exhibited reverse regioselectivity to afford more-substituted alcohols via putative less-stable radicals. DFT calculations indicated that the observed regioselectivity could be explained by shifting the transition states to more reactant-like structures by changing the metal center of the metallocene catalyst.

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“…verted 1AL to 2AL, ring opening of a similar cholesterol (R' = Bz) with titanocene furnished a tertiary radical, and the adjacent hydrogen was abstracted by a cobalt catalyst leading to an allylic alcohol. 38 These contrasting results demonstrated that our catalytic protocol is complementary to conventional methods with titanocene.…”

mentioning

confidence: 95%