Studies on K<sub>2</sub>CO<sub>3</sub>-Catalyzed 1,4-Addition of 1,2-Allenic Ketones with Diethyl Malonate:  Controlled Selective Synthesis of β,γ-Unsaturated Enones and α-Pyrones

Ma, Shengming; Yu, Shichao; Yin, Shaohu

doi:10.1021/jo034633i

Cited by 98 publications

(29 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[17,18] Thus, we tried to extend this chemistry to the organolithiums formed by this conjugated addition reaction (Scheme 5). [19] We initially tested the effect of temperature on the sequential reaction (Table 2).…”

Section: Resultsmentioning

confidence: 99%

Experimental and Theoretical Study of Tunable 1,3‐Lithium Shift of Propargylic/Allenylic Species, Transmetallation, and Pd‐Catalyzed Cross‐Coupling Reactions

Zhao

Liu

et al. 2009

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

The highly selective tuning of the isomerization from 1-arylalka-1,2-dien-1-yllithium to 1-arylalka-1,2-dien-3-yllithium has been realized in the deprotonation of 1-arylalk-1-yne (conditions A and B) and carbolithiation of 1-arylbut-3-en-1-yne with alkyllithium (conditions C and D). Subsequent transmetallation and Pd-catalyzed Negishi coupling reactions afforded 1,1-diaryl or 1,3-diaryl allenes with high selectivity. Deuterium-labeling cross experiments indicated that an intermolecular lithiation process occurred in both 1,3-lithium shift conditions (conditions B and D). 1-Arylalka-1,2-diene was confirmed experimentally to be the intermediate. A computational study at the B3LYP level for the isomerization indicated that the acidity of H at the 3-position is higher than that of the H at the 1-position of 1-phenyl-1,2-butadiene. Under conditions B, iPr(2)NH acts as a proton carrier to finish the 1,3-lithium shift. The overall activation barrier for the rate-determining step in the solvated models is approximately 21.0 kcal mol(-1), indicating that the isomerization is reasonable at room temperature. For the isomerization under conditions D, DFT calculations indicated that the addition of TMEDA (tetramethylethylenediamine) and HMPA (hexamethylphosphoramide) changes the global minimum of the system; among the possible mechanisms (P1-P5) considered, the mechanism catalyzed by dilithiated species (P5) is the most probable one. The overall activation barriers for isomerization in THF and TMEDA solvated models are 22.6 and 19.7 kcal mol(-1), respectively, proving that the isomerization may proceed at RT in THF or at -78 degrees C with TMEDA, due to the fact that the solvation of the additives may increase the concentration of 1-phenyl-1,2-butadienyllithium monomer by a deaggregation effect.

show abstract

Section: Resultsmentioning

confidence: 99%

Experimental and Theoretical Study of Tunable 1,3‐Lithium Shift of Propargylic/Allenylic Species, Transmetallation, and Pd‐Catalyzed Cross‐Coupling Reactions

Zhao

Liu

et al. 2009

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

show abstract

“…Since K 2 CO 3 is known to catalyze certain Michael additions 13,14 and was previously used in the final step in the synthesis of NaPy, we hypothesized that the work-up procedure via recrystallization might have resulted Figure 1. The equilibria between a ditopic supramolecular compound that is able to homo-dimerize and a chain stopper that is unable to dimerize.…”

mentioning

confidence: 99%

Scope and Limitations of Supramolecular Autoregulation

Teunissen

Haas

Vekemans

et al. 2016

Bulletin of the Chemical Society of Japan

View full text Add to dashboard Cite

Recently, our group has reported on the ureidopyrimidinone (UPy) induced buffering of 2,7-diamido-1,8-naphthyridine (NaPy) and used this phenomenon to regulate the catalysis of the Michael addition of 2,4-pentanedione to trans-β-nitrostyrene. We now show that the observed catalytic activity of NaPy is the result of a strong synergy between NaPy and trace amounts of K 2 CO 3 , resulting in a more than 100-fold increase in reaction rate compared to the two compounds separately. By keeping the concentration of K 2 CO 3 , as well as NaPy, constant, an improved regulation of the catalytic activity is achieved. We show that the catalytic activity can be precisely regulated in a noncovalent manner via the addition of the UPy motif. Finally, different salts and Michael substrates are screened to assess the selectivity of this catalytic couple and to provide a platform for future research in molecular buffering, regulation, and chemical networks.

show abstract

“…Column chromatography was performed on silica gel (10-40 u). The starting materials 1a, 12 1b, 12 1c, 12 2a, 12 2b, 12 8a, 14 8b, 14 8c, 14 8d, 14 8e, 14 11a, 15 11b, 15 11c, 15 and 11d 15 were prepared according to literature procedures. …”

Section: Resultsmentioning

confidence: 99%

Highly Regio- and Stereoselective Palladium(0)-Catalyzed Addition of Organoboronic Acids with 1,2-Allenic Sulfones, Sulfoxides, or Alkyl- or Aryl-Substituted Allenes in the Presence of Acetic Acid: An Efficient Synthesis of E-Alkenes

Guo¹,

Ma²

2007

Synthesis

Self Cite

View full text Add to dashboard Cite

show abstract

Studies on K₂CO₃-Catalyzed 1,4-Addition of 1,2-Allenic Ketones with Diethyl Malonate: Controlled Selective Synthesis of β,γ-Unsaturated Enones and α-Pyrones

Cited by 98 publications

References 52 publications

Experimental and Theoretical Study of Tunable 1,3‐Lithium Shift of Propargylic/Allenylic Species, Transmetallation, and Pd‐Catalyzed Cross‐Coupling Reactions

Experimental and Theoretical Study of Tunable 1,3‐Lithium Shift of Propargylic/Allenylic Species, Transmetallation, and Pd‐Catalyzed Cross‐Coupling Reactions

Scope and Limitations of Supramolecular Autoregulation

Highly Regio- and Stereoselective Palladium(0)-Catalyzed Addition of Organoboronic Acids with 1,2-Allenic Sulfones, Sulfoxides, or Alkyl- or Aryl-Substituted Allenes in the Presence of Acetic Acid: An Efficient Synthesis of E-Alkenes

Contact Info

Product

Resources

About

Studies on K2CO3-Catalyzed 1,4-Addition of 1,2-Allenic Ketones with Diethyl Malonate: Controlled Selective Synthesis of β,γ-Unsaturated Enones and α-Pyrones

Cited by 98 publications

References 52 publications

Experimental and Theoretical Study of Tunable 1,3‐Lithium Shift of Propargylic/Allenylic Species, Transmetallation, and Pd‐Catalyzed Cross‐Coupling Reactions

Experimental and Theoretical Study of Tunable 1,3‐Lithium Shift of Propargylic/Allenylic Species, Transmetallation, and Pd‐Catalyzed Cross‐Coupling Reactions

Scope and Limitations of Supramolecular Autoregulation

Highly Regio- and Stereoselective Palladium(0)-Catalyzed Addition of Organoboronic Acids with 1,2-Allenic Sulfones, Sulfoxides, or Alkyl- or Aryl-Substituted Allenes in the Presence of Acetic Acid: An Efficient Synthesis of E-Alkenes

Contact Info

Product

Resources

About

Studies on K₂CO₃-Catalyzed 1,4-Addition of 1,2-Allenic Ketones with Diethyl Malonate: Controlled Selective Synthesis of β,γ-Unsaturated Enones and α-Pyrones