An unexpected rearrangement of pyrazolium halides based on N–N bond cleavage: synthesis of 1,2-dihydropyrimidines

2017 ◽  
Vol 53 (50) ◽  
pp. 6792-6795 ◽  
Author(s):  
Qian Chen ◽  
Xiaoshuang Liu ◽  
Fang Guo ◽  
Zhonglin Chen
Keyword(s):  
Bond Cleavage ◽  
Efficient Approach ◽  
Mild Conditions

An unexpected rearrangement of pyrazolium halides was observed, presenting an efficient approach for the synthesis of 1,2-dihydroquinazolines under mild conditions.

Electron Donation by Low-Crystalline Ba-La-Ce Oxygen-Deficient Composite Oxide Accumulating on Ru Nanoparticles for Ammonia Synthesis under Mild Conditions

2019 ◽  
Author(s):  
Katsutoshi Sato ◽  
Shin-ichiro Miyahara ◽  
Yuta Ogura ◽  
Kotoko Tsujimaru ◽  
Yuichiro Wada ◽  
...  
Keyword(s):  
Ammonia Synthesis ◽  
Bond Cleavage ◽  
Synthesis Process ◽  
Strong Electron ◽  
Mild Conditions ◽  
Ru Nanoparticles ◽  
Rate Determining Step ◽  
Highly Active ◽  
Composite Oxides ◽  
Low Crystalline

<p>To mitigate global problems related to energy and global warming, it is helpful to develop an ammonia synthesis process using catalysts that are highly active under mild conditions. Here we show that the ammonia synthesis activity of Ru/Ba/LaCeO<i><sub>x</sub></i> pre-reduced at 700 °C is the highest reported among oxide-supported Ru catalysts. Our results indicate that low crystalline oxygen-deficient composite oxides, which include Ba<sup>2+</sup>, Ce<sup>3+</sup> and La<sup>3+</sup>, with strong electron-donating ability, accumulate on Ru particles and thus promote N≡N bond cleavage, which is the rate determining step for ammonia synthesis.</p>

Electron Donation by Low-Crystalline Ba-La-Ce Oxygen-Deficient Composite Oxide Accumulating on Ru Nanoparticles for Ammonia Synthesis under Mild Conditions

2019 ◽  
Author(s):  
Katsutoshi Sato ◽  
Shin-ichiro Miyahara ◽  
Yuta Ogura ◽  
Kotoko Tsujimaru ◽  
Yuichiro Wada ◽  
...  
Keyword(s):  
Ammonia Synthesis ◽  
Bond Cleavage ◽  
Synthesis Process ◽  
Strong Electron ◽  
Mild Conditions ◽  
Ru Nanoparticles ◽  
Rate Determining Step ◽  
Highly Active ◽  
Composite Oxides ◽  
Low Crystalline

<p>To mitigate global problems related to energy and global warming, it is helpful to develop an ammonia synthesis process using catalysts that are highly active under mild conditions. Here we show that the ammonia synthesis activity of Ru/Ba/LaCeO<i><sub>x</sub></i> pre-reduced at 700 °C is the highest reported among oxide-supported Ru catalysts. Our results indicate that low crystalline oxygen-deficient composite oxides, which include Ba<sup>2+</sup>, Ce<sup>3+</sup> and La<sup>3+</sup>, with strong electron-donating ability, accumulate on Ru particles and thus promote N≡N bond cleavage, which is the rate determining step for ammonia synthesis.</p>

ChemInform Abstract: Metal Triflate-Catalyzed Se-Se Bond Cleavage and the Selective Additions under Mild Conditions.

ChemInform ◽  
2011 ◽  
Vol 43 (1) ◽  
pp. no-no
Author(s):  
Lei Yu ◽  
Lingfeng Ren ◽  
Rong Guo ◽  
Tian Chen
Keyword(s):  
Bond Cleavage ◽  
Mild Conditions

Organophosphane-Catalyzed Construction of Functionalized 2-Ylideneoxindoles via Direct β-Acylation

Synthesis ◽  
2021 ◽  
Author(s):  
Wey-Chyng Jeng ◽  
Po-Chung Chien ◽  
Sandip Sambhaji Vagh ◽  
Athukuri Edukondalu ◽  
Wenwei Lin
Keyword(s):  
Intramolecular Cyclization ◽  
Efficient Method ◽  
Bond Cleavage ◽  
Scale Up ◽  
Acyl Chlorides ◽  
Metal Free ◽  
Mild Conditions ◽  
Synthetic Utility ◽  
Mechanistic Investigations ◽  
Synthetic Transformations

We report an efficient method for the direct β-acylation of 2-ylideneoxindoles with acyl chlorides in the presence of base-catalyzed by organophosphanes. A variety of functionalized 2-ylideneoxindoles were prepared in moderate to good yields under metal-free and mild conditions via a tandem phospha-Michael/O-acylation/intramolecular cyclization/ rearrangement sequence. The mechanistic investigations revealed that the C-O bond cleavage on possible betaine intermediate is the key step for the installation of keto-functionality at β-position of 2-ylideneoxindoles in a highly stereospecific manner. The synthetic utility of this protocol could also be proven by scale-up reactions and synthetic transformations of the products.

Palladium-Catalyzed Desulfurative Hiyama Coupling of Thioureas to Achieve Amides via Selective C–N Bond Cleavage

Synthesis ◽  
2021 ◽  
Author(s):  
Zhuo Zeng ◽  
Zhanyu He ◽  
Chu Yan ◽  
Mei Zhang ◽  
Majeed Irfan ◽  
...  
Keyword(s):  
Good Yield ◽  
Bond Cleavage ◽  
New Approach ◽  
Mild Conditions ◽  
Palladium Catalyzed

AbstractPalladium-catalyzed Hiyama coupling of active thioureas via selective C–N bond cleavage is reported. Notably, the new approach employed active thioureas as coupling partners in the presence of arylsilanes to give amides in good yield. Further, this strategy, which utilized CuF2 as a key oxidant and activator, afforded various amide products under mild conditions and an easy to handle procedure without extra base.

scholarly journals Decarbonylation through Aldehydic C–H Bond Cleavage by a Cationic Iridium Catalyst

Synlett ◽  
2019 ◽  
Vol 30 (08) ◽  
pp. 972-976 ◽  
Author(s):  
Tomohiko Shirai ◽  
Kazuki Sugimoto ◽  
Masaya Iwasaki ◽  
Ryuki Sumida ◽  
Harunori Fujita ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
Catalyst System ◽  
Mild Conditions ◽  
Iridium Catalyst ◽  
Reaction Proceeds ◽  
High Yields

We report the decarbonylation of aldehydes through an aldehydic C–H bond cleavage catalyzed by a cationic iridium/bisphosphine catalyst. The reaction proceeds under relatively mild conditions to give the corresponding hydrocarbon products in moderate to high yields. In addition, this cationic iridium catalyst system can be applied to an asymmetric hydroacylation of ketones.

Halogen-Radical-Promoted Dearomative Aza-Spirocyclization of Alkynylimines: An Efficient Approach to 3-Halo-Spirocyclohexadienones

Synthesis ◽  
2019 ◽  
Vol 52 (04) ◽  
pp. 609-618 ◽  
Author(s):  
Dianpeng Chen ◽  
Jianming Li ◽  
Yingying Shan ◽  
Peiying Cui ◽  
Yutong Zhao ◽  
...  
Keyword(s):  
Radical Addition ◽  
Efficient Approach ◽  
Mild Conditions ◽  
Halogen Radical

A novel halogen-radical-promoted dearomative aza-spiro­cyclization of alkynylimines for the synthesis of 3-halo-spirocyclohexadienones is described. In this process, it is believed that a radical addition, 5-exo-trig cyclization, and dearomative aza-spirocyclization are involved. Easily available starting materials, mild conditions, and a wide substrate scope make this approach potentially useful.

Palladium-catalyzed [4 + 3] dearomatizing cycloaddition reaction of N-iminoquinolinium ylides

2020 ◽  
Vol 7 (18) ◽  
pp. 2612-2617
Author(s):  
Wenhao Dai ◽  
Chunpu Li ◽  
Yichu Liu ◽  
Xu Han ◽  
Xingjun Li ◽  
...  
Keyword(s):  
Functional Group ◽  
Cycloaddition Reaction ◽  
Membered Ring ◽  
Efficient Approach ◽  
Mild Conditions ◽  
Palladium Catalyzed

An efficient approach to obtain saturated seven-membered ring containing three heteroatoms has been developed by using a palladium-catalyzed [4 + 3] dearomatizing cycloaddition. This approach features mild conditions and good functional group tolerance.

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