Photocatalytic Umpolung Synthesis of Nucleophilic π-Allylcobalt Complexes for Allylation of Aldehydes

Shi, Caizhe; Li, Fusheng; Chen, Yuqing; Lin, Sheng; Hao, Er‐Jun; Guo, Zhuowen; Wosqa, Urwa Tul; Zhang, Dandan; Shi, Lei

doi:10.1021/acscatal.0c05330

Cited by 35 publications

(18 citation statements)

References 51 publications

(67 reference statements)

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“…Next, the aryl Co(III)/ L1 is reduced by another 4CzIPN •– to generate aryl Co(II)/ L1 . After coordination of the aldehyde, aryl Co(II)/ L1 underwent a highly stereospecific Grignard-type addition to the carbon of the carbonyl to generate a chiral alcohol anion. , Finally, protonation occurred, and Co(II)/ L1 dissociated the chiral alcohol. However, we also do not rule out a migration insertion of aldehyde by aryl Co(III)/ L1 …”

Section: Resultsmentioning

confidence: 99%

Photoassisted Cobalt-Catalyzed Asymmetric Reductive Grignard-Type Addition of Aryl Iodides

Jiang

Yang

et al. 2022

J. Am. Chem. Soc.

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Grignard addition is one of the most important methods used for syntheses of alcohol compounds and has been known for over a hundred years. However, research on asymmetric catalysis relies on the use of organometallic nucleophiles. Here, we report the first visible-light-induced cobalt-catalyzed asymmetric reductive Grignard-type addition for synthesizing chiral benzyl alcohols (>50 examples, up to 99% yield, and 99% ee). This methodology has the advantages of mild reaction conditions, good functionality tolerance, excellent enantiocontrol, the avoidance of mass metal wastes, and the use of precious metal catalysts. Kinetic realization studies suggested that migratory insertion of an aryl cobalt species into the aldehyde was the rate-determining step of the reductive addition reaction.

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Section: Resultsmentioning

confidence: 99%

Photoassisted Cobalt-Catalyzed Asymmetric Reductive Grignard-Type Addition of Aryl Iodides

Jiang

Yang

et al. 2022

J. Am. Chem. Soc.

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“…Recently, a similar type of transformation was reported by Shi and co‐workers using allyl and cinnamyl carbonates with variety of aldehydes as coupling partner for the preparation of homoallylic alcohol (Scheme 27). [54] Series of substituents were tolerant under the reaction condition to give the corresponding product in good yield. A plausible reaction mechanism has been proposed on the basis of series of control experiments and photophysical studies (Figure 26).…”

Section: Allylationmentioning

confidence: 99%

Dual Photoredox and Cobalt Catalysis Enabled Transformations

Bajya

Selvakumar

2022

Eur J Org Chem

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Dual photoredox and cobalt catalysis opens a new and exciting avenue for transition metal catalyzed cross-coupling reaction. The ability of this approach to access low valent cobalt species gives enormous opportunity to develop reactions that relies on stoichiometric methods. In this mini review, we have compiled the most recent development of this dual catalytic system with particular attention paid to the mechanistic details and substrate scope. We hope that this review will be useful for synthetic organic chemists and further stimulate the advancement of more novel strategies.

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“…Overall, the catalytic cycle is believed to start with a single‐electron transfer (SET) to the [Co(DPEPhos)Cl 2 ] complex, that then provides a Co III ‐allyl species after an oxidative addition of the allylic surrogate. A second SET gives rise to a nucleophilic Co II ‐allyl intermediate that reacts with the aldehyde reagent via a Zimmerman–Traxler TS [10a,b] . To gain insight into the first step of the mechanism of the reaction, i.e., quenching of the excited state, we performed a Stern–Volmer analysis using both fluorimetry and time‐correlated single‐photon counting (TCSPC).…”

Section: Figurementioning

confidence: 99%

Expedient Dual Co/Organophotoredox Catalyzed Stereoselective Synthesis of All‐Carbon Quaternary Centers

2021

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An efficient and attractive Co/organophotoredox dual catalysis protocol has been developed allowing the stereoselective access to a wide variety of syn-configured 1,3diols featuring quaternary carbon centers. The synthesis of the target molecules is achieved under ambient reaction conditions using modular and accessible reagents, substituted vinyl cyclic carbonates and aldehydes, and in short reaction times. Mechanistic control experiments suggest that the stereoselectivity can be rationalized via a preferred Zimmerman-Traxler transition state comprising a Co(allyl) species and an activated aldehyde. This newly developed process thus expands the use of base metal catalysis in the construction of challenging quaternary carbon stereocenters.

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Photocatalytic Umpolung Synthesis of Nucleophilic π-Allylcobalt Complexes for Allylation of Aldehydes

Cited by 35 publications

References 51 publications

Photoassisted Cobalt-Catalyzed Asymmetric Reductive Grignard-Type Addition of Aryl Iodides

Photoassisted Cobalt-Catalyzed Asymmetric Reductive Grignard-Type Addition of Aryl Iodides

Dual Photoredox and Cobalt Catalysis Enabled Transformations

Expedient Dual Co/Organophotoredox Catalyzed Stereoselective Synthesis of All‐Carbon Quaternary Centers

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