Organoboranes. 38. A facile and highly efficient addition of B-1-alkynyl-9-borabicyclo[3.3.1]nonanes to aldehydes and ketones: an exceptionally chemoselective synthesis of propargylic alcohols

1985 ◽  
Vol 50 (10) ◽  
pp. 1577-1582 ◽  
Author(s):  
Herbert C. Brown ◽  
Gary A. Molander ◽  
Shankar M. Singh ◽  
Uday S. Racherla
Keyword(s):  
Propargylic Alcohols ◽  
Highly Efficient ◽  
Chemoselective Synthesis ◽  
Aldehydes And Ketones

Hafnium(IV) Chloride Catalyzes Highly Efficient Acetalization of Carbonyl Compounds

2019 ◽  
Vol 16 (6) ◽  
pp. 913-920 ◽  
Author(s):  
Israel Bonilla-Landa ◽  
Emizael López-Hernández ◽  
Felipe Barrera-Méndez ◽  
Nadia C. Salas ◽  
José L. Olivares-Romero
Keyword(s):  
Microwave Heating ◽  
Reaction Times ◽  
Protecting Groups ◽  
Catalyst Loading ◽  
Selective Protection ◽  
Highly Efficient ◽  
Aldehydes And Ketones ◽  
High Yields ◽  
Novel Catalyst ◽  
Acid Labile

Background: Hafnium(IV) tetrachloride efficiently catalyzes the protection of a variety of aldehydes and ketones, including benzophenone, acetophenone, and cyclohexanone, to the corresponding dimethyl acetals and 1,3-dioxolanes, under microwave heating. Substrates possessing acid-labile protecting groups (TBDPS and Boc) chemoselectively generated the corresponding acetal/ketal in excellent yields. Aim and Objective: In this study. the selective protection of aldehydes and ketones using a Hafnium(IV) chloride, which is a novel catalyst, under microwave heating was observed. Hence, it is imperative to find suitable conditions to promote the protection reaction in high yields and short reaction times. This study was undertaken not only to find a novel catalyst but also to perform the reaction with substrates bearing acid-labile protecting groups, and study the more challenging ketones as benzophenone. Materials and Methods: Using a microwave synthesis reactor Monowave 400 of Anton Paar, the protection reaction was performed on a raging temperature of 100°C ±1, a pressure of 2.9 bar, and an electric power of 50 W. More than 40 substrates have been screened and protected, not only the aldehydes were protected in high yields but also the more challenging ketones such as benzophenone were protected. All the products were purified by simple flash column chromatography, using silica gel and hexanes/ethyl acetate (90:10) as eluents. Finally, the protected substrates were characterized by NMR 1H, 13C and APCI-HRMS-QTOF. Results: Preliminary screening allowed us to find that 5 mol % of the catalyst is enough to furnish the protected aldehyde or ketone in up to 99% yield. Also it was found that substrates with a variety of substitutions on the aromatic ring (aldehyde or ketone), that include electron-withdrawing and electrondonating group, can be protected using this methodology in high yields. The more challenging cyclic ketones were also protected in up to 86% yield. It was found that trimethyl orthoformate is a very good additive to obtain the protected acetophenone. Finally, the protection of aldehydes with sensitive functional groups was performed. Indeed, it was found that substrates bearing acid labile groups such as Boc and TBDPS, chemoselectively generated the corresponding acetal/ketal compound while keeping the protective groups intact in up to 73% yield. Conclusion: Hafnium(IV) chloride as a catalyst provides a simple, highly efficient, and general chemoselective methodology for the protection of a variety of structurally diverse aldehydes and ketones. The major advantages offered by this method are: high yields, low catalyst loading, air-stability, and non-toxicity.

A highly efficient one-pot trifluoromethylation/cyclization reaction of electron-deficient 1,3-conjugated enynes: modular access to trifluoromethylated furans and 2,3-dihydrofurans

2016 ◽  
Vol 3 (11) ◽  
pp. 1416-1419 ◽  
Author(s):  
Wei Zhou ◽  
Zhenting Yue ◽  
Junliang Zhang
Keyword(s):  
Cyclization Reaction ◽  
One Pot ◽  
Highly Efficient ◽  
Conjugated Enynes ◽  
Aldehydes And Ketones

A highly efficient one-pot trifluoromethylation/cyclization reaction of conjugated enyne aldehydes and ketones was developed, which provides modular access to highly substituted trifluoromethylated furans and 2,3-dihydrofurans.

scholarly journals Thermoregulated phase-separable rhodium nanoparticle catalyst for selective hydrogenation of α,β-unsaturated aldehydes and ketones

RSC Advances ◽  
2017 ◽  
Vol 7 (79) ◽  
pp. 50343-50346 ◽  
Author(s):  
Xiuru Xue ◽  
Mingming Niu ◽  
Yicheng Xu ◽  
Yanhua Wang
Keyword(s):  
Selective Hydrogenation ◽  
Unsaturated Aldehydes ◽  
Highly Efficient ◽  
Aldehydes And Ketones ◽  
Rhodium Nanoparticle ◽  
Nanoparticle Catalyst

Highly efficient and recyclable thermoregulated phase-separable Rhnano catalysts applied for the selective hydrogenation of α,β-unsaturated aldehydes and ketones are presented.

Magnetic nanoparticle-supported phosphine gold(i) complex: a highly efficient and recyclable catalyst for the direct reductive amination of aldehydes and ketones

2016 ◽  
Vol 6 (12) ◽  
pp. 4554-4564 ◽  
Author(s):  
Weisen Yang ◽  
Li Wei ◽  
Feiyan Yi ◽  
Mingzhong Cai
Keyword(s):  
Magnetic Nanoparticle ◽  
Reductive Amination ◽  
Recyclable Catalyst ◽  
Highly Efficient ◽  
Aldehydes And Ketones ◽  
Supported Gold

The direct reductive amination of aldehydes and ketones has been achieved with excellent yields using recyclable magnetic nanoparticle-supported gold(i) catalyst.

Co-N-C catalysts synthesized by pyrolysis of Co-based deep eutectic solvents for aerobic oxidation of alcohols

2018 ◽  
Vol 42 (19) ◽  
pp. 15871-15878 ◽  
Author(s):  
Xin Zhao ◽  
Yan Zhou ◽  
Ai-Ling Jin ◽  
Kuan Huang ◽  
Fujian Liu ◽  
...  
Keyword(s):  
Aerobic Oxidation ◽  
Deep Eutectic Solvents ◽  
Highly Efficient ◽  
Oxidation Of Alcohols ◽  
Aldehydes And Ketones

DES derived Co-N-C composites were used for highly efficient aerobic oxidation of alcohols into the corresponding aldehydes and ketones.

scholarly journals Highly efficient synthesis of alkylidene cyclic carbonates from low concentration CO2 using hydroxyl and azolate dual functionalized ionic liquids

2021 ◽  
Author(s):  
Guiling Shi ◽  
Ran Zhai ◽  
Haoran Li ◽  
Congmin Wang
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Catalytic System ◽  
Cyclic Carbonates ◽  
Efficient Synthesis ◽  
Excellent Performance ◽  
Functionalized Ionic Liquid ◽  
Low Concentration ◽  
Propargylic Alcohols ◽  
Highly Efficient

A dual functionalized ionic liquid catalytic system was developed for the reaction between CO2 and propargylic alcohols, and exhibited excellent performance and good reusability, even under a low concentration of CO2 in a gram-scale reaction.

Sign in / Sign up

Export Citation Format

Share Document