Cobalt‐Catalyzed Enantioselective Hydroboration/Cyclization of 1,7‐Enynes: Asymmetric Synthesis of Chiral Quinolinones Containing Quaternary Stereogenic Centers

Wu, Caizhi; Liao, Jia‐Yu; Ge, Shaozhong

doi:10.1002/anie.201903377

Cited by 62 publications

(25 citation statements)

References 91 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…To develop highly sustainable protocols for asymmetric hydrofuntionalization, several research groups have made tremendous contributions to the development of catalytic organic transformations with earth-abundant metals, including iron, , cobalt, copper, and nickel ,,− (see SI for additional references). Along with several seminal works (see SI for additional references), we among many others including Yun, , Huang, − Buchwald, Ge, − and others (also see SI) have been seeking effective earth-abundant metal catalysts for asymmetric hydroboration and hydrosilylation of alkenes and alkynes. Compared with noble transition metals, earth-abundant metals such as iron possess some advantageous features, such as large reserves, good biocompatibility, and environmental benignity.…”

Section: Introductionmentioning

confidence: 84%

See 1 more Smart Citation

Iron- and Cobalt-Catalyzed Asymmetric Hydrofunctionalization of Alkenes and Alkynes

et al. 2021

View full text Add to dashboard Cite

Conspectus Transition metal catalyzed asymmetric hydrofunctionalization of readily available unsaturated hydrocarbons presents one of the most straightforward and atom-economic protocols to access valuable optically active products. For decades, noble transition metal catalysts have laid the cornerstone in this field, on account of their superior reactivity and selectivity. In recent years, from an economical and sustainable standpoint, first-row, earth-abundant transition metals have received considerable attention, due to their high natural reserves, affordable costs, and low toxicity. Meanwhile, the earth-abundant metal catalyzed hydrofunctionalization reactions have also gained much interest and been investigated gradually. However, since chiral ligand libraries for earth-abundant transition-metal catalysis are limited to date, the development of highly enantioselective versions remains a significant challenge. This Account summarizes our recent efforts in developing suitable chiral ligands for iron and cobalt catalysts and their applications in the highly enantioselective hydrofunctionalization reactions (hydroboration and hydrosilylation) of alkenes and alkynes. In ligand design, we envisioned that chiral unsymmetric NNN-tridentate (UNT) ligand scaffolds could promote these enantioselective transformations with earth-abundant metals. Therefore, several types of chiral UNT ligands were designed and prepared in our laboratory, utilizing readily available natural amino acids as chiral sources. In the very beginning, chiral oxazoline iminopyridine (OIP) ligands were proposed and investigated through the rational combination of nitrogen-containing ligand scaffolds. After a systematic survey of the ligand effects, the imine moiety in the rigid OIP ligands was replaced by a conformationally more flexible amine unit, leading to the construction of reactive oxazoline aminoisopropylpyridine (OAP) ligands. Subsequently, imidazoline iminopyridine (IIP) and thiazoline iminopyridine (TIP) ligands were prepared by altering the oxygen atom of oxazoline with nitrogen and sulfur linkers, respectively. To further expand the chiral ligand library, other tridentate ligands containing a twisted pincer, anionic, and nonrigid backbone were also designed and synthesized, including iminophenyl oxazolinyl phenylamine (IPOPA) and imidazoline phenyl picolinamide (ImPPA). The efficacy of these chiral UNT ligands for asymmetric induction in iron and cobalt catalysis has been demonstrated through asymmetric hydrofunctionalization of alkenes and asymmetric sequential hydrofunctionalization of alkynes, which exhibit excellent reactivity as well as high chemo-, regio-, and stereoselectivity with broad functional group tolerance. Notably, highly regio- and enantioselective hydrofunctionalization of challenging substrates, such as 1,1-disubstituted aryl alkenes and terminal aliphatic alkenes, was also achieved. Furthermore, the development of asymmetric sequential isomerization/hydroboration of internal alkenes and sequential hydrofunctionaliz...

show abstract

Section: Introductionmentioning

confidence: 84%

“…The tridentate OIP ligand led to alkyl boronates and the bidentate iminopyridine ligand gave alkenyl boronates . The Ge group reported cobalt-catalyzed asymmetric hydroboration/cyclization of enynes using chiral bisphosphine ligands. − …”

Section: Asymmetric Hydrofunctionalization Of Alkenesmentioning

confidence: 99%

Iron- and Cobalt-Catalyzed Asymmetric Hydrofunctionalization of Alkenes and Alkynes

et al. 2021

View full text Add to dashboard Cite

show abstract

“…No other work has been reported on this type of cyclisation of diynes, although analogous systems with enynes and dienes have been published. [137][138][139][140][141][142] This reaction was observed to be more effective in dilute solutions. Different ligands and activators, e.g., TMSCH 2 Li, KOAc, t-BuOK could be used, but TBAF 108 and 126 were the most efficient.…”

Section: Hydroboration Of Separated 1n-diynesmentioning

confidence: 98%

Hydroelementation of diynes

et al. 2022

View full text Add to dashboard Cite

show abstract

“…70 Enantioenriched quinolinones can be obtained by enantioselective hydroboration with concomitant cyclization using a cobalt catalyst with chiral phosphine ligands (94-99% ee) (Scheme 22). 71…”

Section: Cyclization 17-enynesmentioning

confidence: 99%

Silylboranes as Powerful Tools in Organic Synthesis: Stereo- and Regioselective Reactions with 1,n-Enynes

Moberg

2020

Synthesis

View full text Add to dashboard Cite

Bismetalated alkenes, accessible by element–element addition to alkynes, are valuable building blocks in organic synthesis, providing wide opportunities for divergent synthesis. Silaboration of alkynes with a pendant olefinic group, catalyzed by group 10 metal complexes, and subsequent transformation of the silicon and boron functional groups give access to densely functionalized 1,3-dienes and 1,3,5-trienes with defined stereo- and regiochemistry, 1,2-dienes, and carbocyclic and heterocyclic products.1 Introduction2 Background3 Reactions with 1,3-Enynes4 Cyclization 1,6-Enynes5 Cyclization 1,7-Enynes6 Cyclization of 1,n-Enynes (n > 7)7 Cyclization of Dienynes and Enediynes8 Cyclization of 1,6-Diynes9 Conclusions

show abstract

Cobalt‐Catalyzed Enantioselective Hydroboration/Cyclization of 1,7‐Enynes: Asymmetric Synthesis of Chiral Quinolinones Containing Quaternary Stereogenic Centers

Cited by 62 publications

References 91 publications

Iron- and Cobalt-Catalyzed Asymmetric Hydrofunctionalization of Alkenes and Alkynes

Iron- and Cobalt-Catalyzed Asymmetric Hydrofunctionalization of Alkenes and Alkynes

Hydroelementation of diynes

Silylboranes as Powerful Tools in Organic Synthesis: Stereo- and Regioselective Reactions with 1,n-Enynes

Contact Info

Product

Resources

About