Organocatalytic Asymmetric Domino Michael/Acyl Transfer Reaction Between α‐Nitroketones and in situ‐Generated ortho‐Quinone Methides: Route to 2‐(1‐Arylethyl)phenols

Gharui, Chandan; Behera, Deepak Kumar; Pan, Subhas Chandra

doi:10.1002/adsc.201801015

Cited by 26 publications

(13 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Initially, a model reaction was studied between trans -α-cyano-α,β-unsaturated ketone 1a and 2-nitro-1-phenylethanone ( 2a ) 13 using different bases in chloroform solvent at room temperature (rt) (Table 1). Using 1,4-diazabicyclo[2.2.2]octane (DABCO) as base, the desired product 3a was formed in only 10% yield as a single trans-diastereomer and the product was confirmed by 1 H, 13 C NMR analysis.…”

Section: Resultsmentioning

confidence: 99%

DBU-Mediated Addition of α-Nitroketones to α-Cyano-enones and α,β-Unsaturated α-Ketoesters: Synthesis of Dihydrofurans and Conjugated Dienes

Maity

Pan

2019

ACS Omega

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Resultsmentioning

confidence: 99%

DBU-Mediated Addition of α-Nitroketones to α-Cyano-enones and α,β-Unsaturated α-Ketoesters: Synthesis of Dihydrofurans and Conjugated Dienes

Maity

Pan

2019

ACS Omega

Self Cite

View full text Add to dashboard Cite

show abstract

“…In 2018, Pan and co‐workers anticipated bifunctional squaramide catalyzed enantioselective domino Michael/acyl transfer reaction between in situ formed o ‐QM and α ‐nitro ketone 44 for an expedient synthesis of chiral O ‐acyl‐2‐(1‐arylethyl)phenols 45 (Scheme ) . 2‐sulfonylmethylphenols were chosen as the suitable precursor of ortho ‐quinone methides.…”

Section: Asymmetric Reactions With O‐qmsmentioning

confidence: 99%

Applications of Bifunctional Organocatalysts on ortho‐Quinone Methides

2019

Self Cite

View full text Add to dashboard Cite

ortho-Quinone methides are important structures, having a cyclohexadiene core bearing an exocyclic alkylidiene and carbonyl functionality at the ortho-position, and are widely used as essential intermediates in organic synthesis. These reactive intermediates are also used as important building blocks for the construction of a variety of heterocycles by hetero Diels-Alder, electrocyclization reactions. Moreover, ortho-quinone methides are a class of electrophiles, serving as Michael acceptors leading to conjugate additions with various nucleophiles. In general, ortho-Quinone methides have transient existence and are highly reactive in nature. ortho-Quinone methides have been generated in situ from stable precursors using either Brønsted acids or Brønsted bases. In the last few years, ortho-quinone methides have been explored as imperative class of substrates in various bifunctional organocatalysts mediated asymmetric conjugate additions, cycloannulation, acyl-transfer reaction, thiolation and hydrophosphination reactions. This review illustrates recent advancements of asymmetric transformations of ortho-quinone methides with bifunctional H-bonding organocatalysts.[a] S.

show abstract

“…With an appropriate tool to activate -nitroketones, the scope was extended to the addition to in situ generated ortho-quinone methides (Scheme 12). 18 Generation of this reactive species from 26 by NaHCO 3 -promoted sulfone elimination induces the subsequent catalyzed Michael addition, affording a phenol able to promote the acyl transfer. As observed for other transformations, control experiments with nitroalkane pro-nucleophiles did not give any Michael addition, which serves to highlight the interest of the approach.…”

Section: Short Review Syn Thesis Scheme 11 Addition Of Nitroketones Tmentioning

confidence: 99%

Acyl Transfer Strategies as Transient Activations for Enantioselective Synthesis

Rodríguez¹,

Quintard

2019

Synthesis

View full text Add to dashboard Cite

In order to circumvent reactivity or selectivity issues associated with the addition of enolates to electrophiles, chemists have devised innovative methods involving transient activating groups. One of these powerful methods consists of the use of activated ketones, such as α-nitroketones, β-dicarbonyl compounds or β-ketosulfones, with electrophiles possessing a latent hydroxy or amine function. In the presence of a suitable catalyst, an enantioselective addition to the electrophile is facilitated triggering a subsequent Claisen-type fragmentation resulting in an acyl transfer. This subsequent step unveils the desired mono-activated function while directly transferring the ketone, forming in situ on the other side an ester or an amide.1 Introduction2 Intramolecular Acyl Transfer with Acyclic Substrates2.1 Bifunctional Catalysis2.2 Aminocatalysis3 Intermolecular Acyl Transfer with Acyclic Substrates4 Medium-Sized-Ring Formation with Cyclic Substrates5 Conclusion

show abstract

Organocatalytic Asymmetric Domino Michael/Acyl Transfer Reaction Between α‐Nitroketones and in situ‐Generated ortho‐Quinone Methides: Route to 2‐(1‐Arylethyl)phenols

Cited by 26 publications

References 39 publications

DBU-Mediated Addition of α-Nitroketones to α-Cyano-enones and α,β-Unsaturated α-Ketoesters: Synthesis of Dihydrofurans and Conjugated Dienes

DBU-Mediated Addition of α-Nitroketones to α-Cyano-enones and α,β-Unsaturated α-Ketoesters: Synthesis of Dihydrofurans and Conjugated Dienes

Applications of Bifunctional Organocatalysts on ortho‐Quinone Methides

Acyl Transfer Strategies as Transient Activations for Enantioselective Synthesis

Contact Info

Product

Resources

About