Stoichiometry Dependence in the Consecutive, Competing Reduction, Halogenation, or Deoxygenation of Aryl Carbonyls DOI
P. Veeraraghavan Ramachandran, Henry J. Hamann,

Abdulkhaliq A. Alawaed

et al.

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 20, 2024

Six fundamental chemical transformations of aryl carbonyls are achieved by properly adjusting the stoichiometry borane-amine and titanium tetrachloride reagent system. This set reagents acts collectively as a hydride donor, Lewis acid catalyst, halogen source for reduction to alcohols, reductive halogenation halides, deoxygenation alkanes, dehydroxyhalogenation alcohols hydrodehalogenation halides alkanes. While carbonyl is broadly applicable both aromatic aliphatic substrates, remaining reactions dependent on stability proposed carbocationic intermediates, enabling highly selective at substrates' benzylic position. unique selectivity allows dehalogenation in presence alkyl addition even tertiary versus secondary primary substrates using only chlorinating agent.

Language: Английский

TiCl4-mediated deoxygenative reduction of aromatic ketones to alkylarenes with ammonia borane DOI
Yongjun Zang,

Yunfeng Ma,

Qilin Xu

et al.

Organic & Biomolecular Chemistry, Journal Year: 2024, Volume and Issue: 22(5), P. 932 - 939

Published: Jan. 1, 2024

A rapid and mild protocol for the exhaustive deoxygenation of various aromatic ketones to corresponding alkanes using AB as a reductant TiCl 4 catalyst.

Language: Английский

Citations

5
A Safer Reduction of Carboxylic Acids with Titanium Catalysis DOI
P. Veeraraghavan Ramachandran,

Abdulkhaliq A. Alawaed,

Henry J. Hamann

et al.

Organic Letters, Journal Year: 2022, Volume and Issue: 24(46), P. 8481 - 8486

Published: Nov. 15, 2022

Ammonia-borane, shown previously to react with carboxylic acids under reflux form primary amides, reduces alcohols at room temperature in the presence of catalytic TiCl4. The process, which is tolerant a variety potentially reactive functional groups, including N-protected amino acids, can be employed for selective reduction nitriles and, some extent, esters. Aliphatic selectively reduced aromatic acids.

Language: Английский

Citations

22
Ni(II)-Catalyzed Transfer Hydrogenation of Azoarenes with NH3BH3 DOI
Dawei Gong,

Degong Kong,

Yufei Li

et al.

Organic Letters, Journal Year: 2023, Volume and Issue: 25(22), P. 4198 - 4202

Published: May 31, 2023

A nickel-catalyzed semihydrogenation of azoarenes to hydrazoarenes with NH3BH3 is developed. The catalytic system exhibits good functional group tolerance and a high turnover frequency at room temperature. Results control deuterium-labeling experiments indicate that the ethanol hydroxyl BH3 groups each donated one hydrogen this transfer hydrogenation, main byproducts were B(OEt)3 H2. Moreover, density theory calculations indicated reaction proceeded via ligand-to-ligand mechanism. This study presents novel nickel for azoarenes.

Language: Английский

Citations

12
Catalyst- and Stoichiometry-Dependent Deoxygenative Reduction of Esters to Ethers or Alcohols with Borane–Ammonia DOI
P. Veeraraghavan Ramachandran,

Abdulkhaliq A. Alawaed,

Henry J. Hamann

et al.

Organic Letters, Journal Year: 2023, Volume and Issue: 25(37), P. 6902 - 6906

Published: Sept. 10, 2023

A facile and selective room temperature deoxygenation of both aromatic aliphatic carboxylic esters to ethers has been achieved by regulating the stoichiometry reductant, BH3–NH3, catalyst, TiCl4. This first, practical borane-mediated process is compatible with various potentially sensitive functional groups applicable deoxygenative ether formation from typically challenging acid esters. Substituting BF3–Et2O as catalyst alters reaction pathway, reducing alcohols. Mechanistic insights are provided NMR spectroscopy, deuterium labeling, kinetic isotope studies.

Language: Английский

Citations

12
Balancing Lewis Acidity and Carbocation Stability for the Selective Deoxyhalogenation of Aryl Carbonyls and Carbinols DOI
P. Veeraraghavan Ramachandran,

Abdulkhaliq A. Alawaed,

Henry J. Hamann

et al.

Organic Letters, Journal Year: 2023, Volume and Issue: 25(25), P. 4650 - 4655

Published: June 15, 2023

Deoxyhalogenation of aryl aldehydes, ketones, carboxylic acids, and esters has been achieved utilizing an appropriate metal halide Lewis acid acting as a carbonyl activator halogen carrier in combination with borane-ammonia the reductant. Selectivity is accomplished by matching stability carbocation intermediate effective acidity acid. Substituents substitution patterns significantly influence requisite solvent/Lewis combination. Logical combinations these factors have also applied for regioselective conversion alcohols to alkyl halides.

Language: Английский

Citations

11
Titanium-Mediated Reduction of Carboxamides to Amines with Borane–Ammonia DOI Creative Commons
P. Veeraraghavan Ramachandran,

Abdulkhaliq A. Alawaed,

Aman Singh

et al.

Molecules, Journal Year: 2023, Volume and Issue: 28(12), P. 4575 - 4575

Published: June 6, 2023

In this study, the successful titanium tetrachloride-catalyzed reduction of aldehydes, ketones, carboxylic acids, and nitriles with borane-ammonia was extended to (deoxygenation) a variety aromatic aliphatic pri-, sec- tert-carboxamides, by changing stoichiometry catalyst reductant. The corresponding amines were isolated in good excellent yields, following simple acid-base workup.

Language: Английский

Citations

8
TiF4-catalyzed direct amidation of carboxylic acids and amino acids with amines DOI Creative Commons

Abdulkhaliq A. Alawaed,

P. Veeraraghavan Ramachandran

Organic & Biomolecular Chemistry, Journal Year: 2024, Volume and Issue: 22(9), P. 1915 - 1919

Published: Jan. 1, 2024

Catalytic titanium tetrafluoride enables the direct amidation of aromatic and aliphatic carboxylic acids N -protected amino with amines, yielding structurally diverse carboxamide peptide products.

Language: Английский

Citations

3
Aryl carbonyls and carbinols as proelectrophiles for Friedel–Crafts benzylation and alkylation DOI Creative Commons
P. Veeraraghavan Ramachandran,

Randy Lin,

Abdulkhaliq A. Alawaed

et al.

RSC Advances, Journal Year: 2024, Volume and Issue: 14(22), P. 15554 - 15559

Published: Jan. 1, 2024

Friedel–Crafts benzylation/alkylation using benzylic alcohols and aryl carbonyls as proelectrophiles is achieved borane-ammonia TiCl 4 .

Language: Английский

Citations

2
TiCl4-catalyzed deoxygenative reduction of amides to amines using ammonia borane DOI
Yongjun Zang, Qibang Sui, Qilin Xu

et al.

Tetrahedron Letters, Journal Year: 2023, Volume and Issue: 124, P. 154598 - 154598

Published: June 15, 2023

Language: Английский

Citations

6
Amidophosphine Boranes as Hydroboration Reagents for Nitriles, Alkynes, and Carboxylic Acids DOI
Ravi Kumar,

Rohan Kumar Meher,

Jyoti Sharma

et al.

Organic Letters, Journal Year: 2023, Volume and Issue: 25(43), P. 7923 - 7927

Published: Oct. 26, 2023

We report here the hydroboration of nitriles, alkynes, and carboxylic acids using amidophosphine boranes {(BH3)(PPh2)-NC(CH3)3}, {(BH3)2(PPh)2N(CH2)C6H5}, {(BH3)2(PPh2)2N-(BH3)CH2C6H4N} as reducing agents. These compounds were synthesized to replace more commonly used borane reagents. Solid boranes, which with ease, demonstrated excellent reactivity functional group tolerance toward a wide variety acids, affording corresponding ammonium salts, alkenes, alcohols in good yield.

Language: Английский

Citations

5