Catalytic Enantioconvergent Allenylation of Aldehydes with Propargyl Halides

Zhang, Fenghua; Guo, Xiaochong; Zeng, Xianrong; Wang, Zhaobin

doi:10.1002/anie.202117114

Cited by 37 publications

(17 citation statements)

References 118 publications

(13 reference statements)

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“…Despite the fact that the reaction offers superior selectivity, among carbonyl compounds, for aldehydes, superstoichiometric amounts of chromium salts are invariably required, strongly curbing sustainability and atom economy. , In 1996, Fürstner and co-workers seminally developed a catalytic NHK reaction by employing manganese powder as the stoichiometric reductant and TMSCl as an additive to cleave the incipient C–Cr bond . Since then, chromium catalytic strategies have reached remarkable levels of sophistication, for instance, by exploiting electrochemical conditions or subtly controlling axial chirality . Inspired by recent developments in metallaphotoredox chemistry, our group started to investigate dual chromium/photoredox catalytic manifolds.…”

Section: Dual Chromium and Photoredox Catalysismentioning

confidence: 99%

“…41 Since then, chromium catalytic strategies have reached remarkable levels of sophistication, for instance, by exploiting electrochemical conditions 42 or subtly controlling axial chirality. 43 Inspired by recent developments in metallaphotoredox chemistry, 25 our group started to investigate dual chromium/photoredox catalytic manifolds. By leveraging photoredox chemistry, the classic NHK reaction can be developed into a milder and sustainable strategy that is complementary to classic carbonyl addition reactions.…”

Section: Catalytic Generation Of Allylic Chromium Intermediatesmentioning

confidence: 99%

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Merging Carbonyl Addition with Photocatalysis

Huang

Glorius

2022

Acc. Chem. Res.

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The carbonyl group stands as a fundamental scaffold and plays a ubiquitous role in synthetically important chemical reactions in both academic and industrial contexts. Venerable transformations, including the aldol reaction, Grignard reaction, Wittig reaction, and Nozaki− Hiyama−Kishi reaction, constitute a vast and empowering synthetic arsenal. Notwithstanding, twoelectron mechanisms inherently confine the breadth of accessible reactivity and topological patterns. Fostered by the rapid development of photoredox catalysis, combing well-entrenched carbonyl addition and radicals can harness several unique and increasingly sustainable transformations. In particular, unusual carbon−carbon and carbon−heteroatom disconnections, which are out of reach of two-electron carbonyl chemistry, can be conceived. To meet this end, a novel strategy toward the utilization of simple carbonyl compounds as intermolecular radical acceptors was developed. The reaction is enabled by visible-light photoredox-initiated hole catalysis. In situ Brønsted acid activation of the carbonyl moiety prevents β-scission from occurring. Furthermore, this regioselective alkyl radical addition reaction obviates the use of metals, ligands, or additives, thus offering a high degree of atom economy under mild conditions. On the basis of the same concept and the work of Schindler and co-workers, carbonyl−olefin cross-metathesis, induced by visible light, has also been achieved, leveraging a radical Prins-elimination sequence. Recently, dual chromium and photoredox catalysis has been developed by us and Kanai, offering a complementary approach to the revered Nozaki−Hiyama−Kishi reaction. Leveraging the intertwined synergy between light and metal, several radical-to-polar crossover transformations toward eminent molecular motifs have been developed. Reactions such as the redox-neutral allylation of aldehydes and radical carbonyl alkylation can harvest the power of light and enable the use of catalytic chromium metal. Overall, exquisite levels of diastereoselectivity can be enforced via highly compact transition states. Other examples, such as the dialkylation of 1,3-dienes and radical carbonyl propargylation portray the versatile combination of radicals and carbonyl addition in multicomponent coupling endeavors. Highly valuable motifs, which commonly occur in complex drug and natural product architectures, can now be accessed in a single operational step. Going beyond carbonyl addition, seminal contributions from Fagnoni and MacMillan preconized photocatalytic HAT-based acyl radical formation as a key aldehyde valorization strategy. Our group articulated this concept, leveraging carboxy radicals as hydrogen atom abstractors in high regio-and chemoselective carbonyl alkynylation and aldehyde trifluoromethylthiolation. This Account, in addition to the narrative of our group and others' contributions at the interface between carbonyl addition and radical-based photochemistry, aims to provide core guiding foundations toward novel disruptive synthetic development...

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Section: Dual Chromium and Photoredox Catalysismentioning

confidence: 99%

Section: Catalytic Generation Of Allylic Chromium Intermediatesmentioning

confidence: 99%

Merging Carbonyl Addition with Photocatalysis

Huang

Glorius

2022

Acc. Chem. Res.

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“…Later on, Qin developed a direct cross-coupling between terminal alkynes and glycosyl acetates, which was applied to the formal synthesis of (+)- 123 and analogues [ 112 ]. More recently, Wang and coworkers reported another formal synthesis of (+)-123 [ 113 ]. They developed a chromium-catalyzed enantioconvergent allenylation of aldehydes to synthesize α-allenols from racemic propargyl halides.…”

Section: Other Tetrahydrofuran Derivativesmentioning

confidence: 99%

The Tetrahydrofuran Motif in Marine Lipids and Terpenes

et al. 2022

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Heterocycles are particularly common moieties within marine natural products. Specifically, tetrahydrofuranyl rings are present in a variety of compounds which present complex structures and interesting biological activities. Focusing on terpenoids, a high number of tetrahydrofuran-containing metabolites have been isolated during the last decades. They show promising biological activities, making them potential leads for novel antibiotics, antikinetoplastid drugs, amoebicidal substances, or anticancer drugs. Thus, they have attracted the attention of the synthetics community and numerous approaches to their total syntheses have appeared. Here, we offer the reader an overview of marine-derived terpenoids and related compounds, their isolation, structure determination, and a special focus on their total syntheses and biological profiles.

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“…As part of our ongoing efforts in asymmetric carbonyl addition using chiral alkyl Cr complexes via reductive radical-polar crossover, we anticipated that alkyl Cr complexes might be stabilized by an α-substituted sulfur or selenium group and thus fulfill the nucleophilic addition to aldehydes. In 1986, Takai and co-workers reported the reductive coupling of α-halo sulfides and aldehydes with stoichiometric amounts of CrCl 2 in moderate to good diastereoselectivities .…”

mentioning

confidence: 99%

Cr-Catalyzed Diastereo- and Enantioselective Synthesis of β-Hydroxy Sulfides and Selenides

Xia

Wang

2022

ACS Catal.

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The Cr-catalyzed Nozaki–Hiyama–Kishi reaction serves as a reliable and valuable C–C bond construction strategy in organic synthesis. However, known Cr-catalyzed asymmetric transformations are limited mainly to primary Cr intermediates with an α-substituted π-functional group, which impeded their further synthetic applications. Herein, we described a Cr-catalyzed three-component reaction, which provides modular access to valuable chiral β-hydroxy sulfides and selenides with vicinal stereocenters. Based on preliminary mechanistic studies, this method proceeds via the asymmetric reductive radical-polar crossover, featuring unprecedented secondary chiral alkyl Cr complex stabilized by the α-sulfur or selenium.

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Catalytic Enantioconvergent Allenylation of Aldehydes with Propargyl Halides

Cited by 37 publications

References 118 publications

Merging Carbonyl Addition with Photocatalysis

Merging Carbonyl Addition with Photocatalysis

The Tetrahydrofuran Motif in Marine Lipids and Terpenes

Cr-Catalyzed Diastereo- and Enantioselective Synthesis of β-Hydroxy Sulfides and Selenides

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