In Situ Generation of Diimide from Hydrazine and Oxygen: Continuous‐Flow Transfer Hydrogenation of Olefins

Pieber, Bartholomäus; Martinez, Sabrina T.; Cantillo, David; Kappe, C. Oliver

doi:10.1002/anie.201303528

Cited by 84 publications

(43 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Presumably, the reduced form of the DMP generated in this process is 'recycled' by atmospheric oxygen. [19] In keeping with such proposals, when a sample of pure allylic alcohol 14 was treated in a vessel open to the air with a combination of hydrazine, acetic acid, and 2 mol-% DMP at ambient temperatures for 48 h, compound 13 was obtained in a yield of 77 % (at 62 % conversion) after column chromatography.…”

Section: Resultsmentioning

confidence: 97%

The Conversion of Levoglucosenone into Isolevoglucosenone

Anderson

White

et al. 2015

Aust. J. Chem.

View full text Add to dashboard Cite

Levoglucosenone (1), a compound that will soon be available in tonne quantities through the pyrolysis of acid-treated lignocellulosic biomass, has been converted into isolevoglucosenone (2) using Wharton rearrangement chemistry. Treatment of compound 1 with alkaline hydrogen peroxide gave the g-lactones 5 and 6 rather than the required epoxyketones 3 and/or 4. However, the latter pair of compounds could be obtained by an initial Luche reduction of compound 1, electrophilic epoxidation of the resulting allylic alcohol 8 and oxidation of the product oxiranes 9 and 10. Independent treatment of compounds 3 and 4 with hydrazine then acetic acid followed by oxidation of the ensuing allylic alcohols finally afforded isolevoglucosenone (2). Details of the single-crystal X-ray analyses of epoxy-alcohols 9 and 10 are reported.

show abstract

Section: Resultsmentioning

confidence: 97%

The Conversion of Levoglucosenone into Isolevoglucosenone

Anderson

White

et al. 2015

Aust. J. Chem.

View full text Add to dashboard Cite

show abstract

“…Kappe and coworkers could show that a continuous flow protocol in a high-temperature/highpressure regime significantly enhances this process and thus eliminates the need for a catalyst [139,140]. In the original procedure, an organic stream consisting of an olefin and hydrazine hydrate in n-propanol was mixed with oxygen resulting in a segmented flow pattern which is heated in a residence time unit to 100-120 C at a back pressure of 20 bar [139]. Reaction times of 10-30 min were sufficient to selectively reduce various terminal and internal carbon-carbon double bonds.…”

Section: Oxidative Carbon-carbon Coupling Reactionsmentioning

confidence: 98%

“…Since the initial oxidation step is rather slow under laboratory batch conditions, catalysts are usually added in order to provide a feasible experimental protocol. Kappe and coworkers could show that a continuous flow protocol in a high-temperature/highpressure regime significantly enhances this process and thus eliminates the need for a catalyst [139,140]. In the original procedure, an organic stream consisting of an olefin and hydrazine hydrate in n-propanol was mixed with oxygen resulting in a segmented flow pattern which is heated in a residence time unit to 100-120 C at a back pressure of 20 bar [139].…”

Section: Oxidative Carbon-carbon Coupling Reactionsmentioning

confidence: 99%

Aerobic Oxidations in Continuous Flow

Pieber

Kappe

2015

Organometallic Flow Chemistry

Self Cite

View full text Add to dashboard Cite

In recent years, the high demand for sustainable processes resulted in the development of highly attractive oxidation protocols utilizing molecular oxygen or even air instead of more uneconomic and often toxic reagents. The application of these sustainable, gaseous oxidants in conventional batch reactors is often associated with severe safety risks and process challenges especially on larger scales. Continuous flow technology offers the possibility to minimize these safety hazards and concurrently allows working in high-temperature/high-pressure regimes to access highly efficient oxidation protocols. This review article critically discusses recent literature examples of flow methodologies for selective aerobic oxidations of organic compounds. Several technologies and reactor designs for biphasic gas/liquid as well as supercritical reaction media are presented in detail.

show abstract

“…4 Although chip reactors can be used independently or in conjunction with other chip reactors, they are often employed as pre-mixers to larger milliscale "coil" reactors. 32 Microfluidic reactors are often characterised as either active or passive, in reference to the micromixers which they usually contain. Active mixing requires an external input such as vibrational or electrical forces to enhance mixing efficiency, whereas passive mixers rely on molecular diffusion and chaotic advection.…”

Section: Microfluidic Technologymentioning

confidence: 99%