Tetrahydropyran synthesis via radical cyclization. A systematic study of substituent effects

1991 ◽  
Vol 113 (6) ◽  
pp. 2335-2336 ◽  
Author(s):  
Steven D. Burke ◽  
Jean Rancourt
Keyword(s):  
Systematic Study ◽  
Substituent Effects ◽  
Radical Cyclization

Substituent effects on 2-aza-5-hexynyl radical cyclization regiochemistry

1982 ◽  
Vol 23 (46) ◽  
pp. 4765-4768 ◽  
Author(s):  
Joong-Kwon Choi ◽  
David J. Hart ◽  
Yeun-Min Tsai
Keyword(s):  
Substituent Effects ◽  
Radical Cyclization

Diastereoselective alkylations of chiral, phosphorus-stabilized carbanions: N-alkyl substituent effects in P-alkyl-1,3,2-diazaphosphorinane 2-oxides

2000 ◽  
Vol 78 (6) ◽  
pp. 673-688 ◽  
Author(s):  
Scott E Denmark ◽  
Jung-Ho Kim
Keyword(s):  
Systematic Study ◽  
Substituent Effects ◽  
Alkyl Substituent

A systematic study of the diastereoselective alkylation of anions derived from racemic N-substituted P-alkyl 1,3,2-diazaphosphorinane 2-oxides was carried out with variation of the N-substituent. High diastereoselectivity for the methylation of a P-benzyl anion has been achieved with N-neopentyl derivative 5d. Similarly, a P-ethyl anion derived from N-neopentyl derivative 6d showed high diastereoselectivity upon benzylation. The observed difference in alkylation diastereoselectivity between P-ethyl and P-benzyl anions for various N-alkyl substituents is discussed.Key words: phosphonamide-stabilized carbanions, alkylation, asymmetric, stereoselective, organolitihium.

scholarly journals Structure-Photochemical Function Relationships in Nitrogen-Containing Heterocyclic Aromatic Photobases Derived from Quinoline

2019 ◽  
Author(s):  
Sophya Alamudun ◽  
Kyle Tanovitz ◽  
April Fajardo ◽  
Kaitlind Johnson ◽  
Andy Pham ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Excitation Energy ◽  
Systematic Study ◽  
Experimental Studies ◽  
Substituent Effects ◽  
Vertical Excitation ◽  
Vertical Excitation Energy ◽  
Heterocyclic Aromatics ◽  
A Charge

<p>Photobases are compounds which become strong bases after electronic excitaton into a charge-transfer excited state. Recent experimental studies have highlighted the photobasicity of the 5-R quinoline compounds, demonstrating a strong substituent dependence to the pK<sub>a</sub><sup>*</sup>. Here we describe our systematic study of how the photobasicity of four families of nitrogen-containing heterocyclic aromatics are tuned through substituents. We show that substituent position and identity both significantly impact the pK<sub>a</sub><sup>*</sup>. We demonstrate that the substituent effects are additive and identify many disubstituted compounds with substantially greater photobasicity than the most photobasic 5-R quinoline compound identified previously. We show that the addition of a second fused benzene ring to quinoline, along with two electron-donating substituents, lowers the vertical excitation energy into the visible while still maintaining a pK<sub>a</sub><sup>*</sup> > 14. Overall, the structure-function relationships developed in this study provide new insights to guide the development of new photocatalysts that employ photobasicity. </p>

Structure-Photochemical Function Relationships in Nitrogen-Containing Heterocyclic Aromatic Photobases Derived from Quinoline

2020 ◽  
Author(s):  
Sophya Alamudun ◽  
Kyle Tanovitz ◽  
April Fajardo ◽  
Kaitlind Johnson ◽  
Andy Pham ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Excitation Energy ◽  
Systematic Study ◽  
Experimental Studies ◽  
Substituent Effects ◽  
Vertical Excitation ◽  
Vertical Excitation Energy ◽  
Heterocyclic Aromatics ◽  
A Charge

<p>Photobases are compounds which become strong bases after electronic excitaton into a charge-transfer excited state. Recent experimental studies have highlighted the photobasicity of the 5-R quinoline compounds, demonstrating a strong substituent dependence to the pK<sub>a</sub><sup>*</sup>. Here we describe our systematic study of how the photobasicity of four families of nitrogen-containing heterocyclic aromatics are tuned through substituents. We show that substituent position and identity both significantly impact the pK<sub>a</sub><sup>*</sup>. We demonstrate that the substituent effects are additive and identify many disubstituted compounds with substantially greater photobasicity than the most photobasic 5-R quinoline compound identified previously. We show that the addition of a second fused benzene ring to quinoline, along with two electron-donating substituents, lowers the vertical excitation energy into the visible while still maintaining a pK<sub>a</sub><sup>*</sup> > 14. Overall, the structure-function relationships developed in this study provide new insights to guide the development of new photocatalysts that employ photobasicity. </p>

Assemblies of salen-type oxidovanadium(iv) complexes: substituent effects and in vitro protein tyrosine phosphatase inhibition

2014 ◽  
Vol 43 (45) ◽  
pp. 17044-17053 ◽  
Author(s):  
Piotr Zabierowski ◽  
Janusz Szklarzewicz ◽  
Ryszard Gryboś ◽  
Barbara Modryl ◽  
Wojciech Nitek
Keyword(s):  
Systematic Study ◽  
Protein Tyrosine Phosphatase ◽  
Tyrosine Phosphatase ◽  
Substituent Effects ◽  
Complex Molecules ◽  
Protein Tyrosine ◽  
Phosphatase Inhibition ◽  
Vitro Protein

A systematic study of 5,5′-disubstituted oxidovanadium(iv) complexes with a chiral salen type ligand showed variable assemblies of complex molecules dependent on steric and electronic factors of the substituents.

scholarly journals Structure-Photochemical Function Relationships in Nitrogen-Containing Heterocyclic Aromatic Photobases Derived from Quinoline

2020 ◽  
Author(s):  
Sophya Alamudun ◽  
Kyle Tanovitz ◽  
April Fajardo ◽  
Kaitlind Johnson ◽  
Andy Pham ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Excitation Energy ◽  
Systematic Study ◽  
Experimental Studies ◽  
Substituent Effects ◽  
Vertical Excitation ◽  
Vertical Excitation Energy ◽  
Heterocyclic Aromatics ◽  
A Charge

<p>Photobases are compounds which become strong bases after electronic excitaton into a charge-transfer excited state. Recent experimental studies have highlighted the photobasicity of the 5-R quinoline compounds, demonstrating a strong substituent dependence to the pK<sub>a</sub><sup>*</sup>. Here we describe our systematic study of how the photobasicity of four families of nitrogen-containing heterocyclic aromatics are tuned through substituents. We show that substituent position and identity both significantly impact the pK<sub>a</sub><sup>*</sup>. We demonstrate that the substituent effects are additive and identify many disubstituted compounds with substantially greater photobasicity than the most photobasic 5-R quinoline compound identified previously. We show that the addition of a second fused benzene ring to quinoline, along with two electron-donating substituents, lowers the vertical excitation energy into the visible while still maintaining a pK<sub>a</sub><sup>*</sup> > 14. Overall, the structure-function relationships developed in this study provide new insights to guide the development of new photocatalysts that employ photobasicity. </p>

scholarly journals Substituent effects of bridged binaphthyl-type chiral dopants on the helical twisting power in dopant-induced chiral liquid crystals

RSC Advances ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. 971-979 ◽  
Author(s):  
Yu Narazaki ◽  
Hiroya Nishikawa ◽  
Hiroki Higuchi ◽  
Yasushi Okumura ◽  
Hirotsugu Kikuchi
Keyword(s):  
Liquid Crystals ◽  
Systematic Study ◽  
Substituent Effects ◽  
Chiral Dopants ◽  
Chiral Liquid Crystals ◽  
Helical Twisting Power

A systematic study of the induced helical twisting power by the 6,6′-substituted bridged binaphthyl-type chiral dopants.

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