scholarly journals Remarkable Alkene-to-Alkene and Alkene-to-Alkyne Transfer Reactions of Selenium Dibromide and PhSeBr. Stereoselective Addition of Selenium Dihalides to Cycloalkenes

Molecules ◽  
2020 ◽  
Vol 25 (1) ◽  
pp. 194
Author(s):  
Vladimir A. Potapov ◽  
Maxim V. Musalov ◽  
Evgeny O. Kurkutov ◽  
Vladimir A. Yakimov ◽  
Alfiya G. Khabibulina ◽  
...  
Keyword(s):  
Room Temperature ◽  
Stereoselective Synthesis ◽  
Reaction Pathway ◽  
Transfer Reactions ◽  
Addition Reactions ◽  
Group Transfer ◽  
Unsaturated Compounds ◽  
Stereoselective Addition ◽  
Selenium Dibromide ◽  
Original Goal

The original goal of this research was to study stereochemistry of selenium dihalides addition to cycloalkenes and properties of obtained products. Remarkable alkene-to-alkene and alkene-to-alkyne transfer reactions of selenium dibromide and PhSeBr were discovered during this research. The adducts of selenium dibromide with alkenes or cycloalkenes easily exchange SeBr2 with other unsaturated compounds, including acetylenes, at room temperature, in acetonitrile. Similar alkene-to-alkene and alkene-to-alkyne transfer reactions of the PhSeBr adducts with alkenes or cycloalkenes take place. The supposed reaction pathway includes the selenium group transfer from seleniranium species to alkenes or alkynes. It was found that the efficient SeBr2 and PhSeBr transfer reagents are Se(CH2CH2Br)2 and PhSeCH2CH2Br, which liberate ethylene, leading to a shift in equilibrium. The regioselective and stereoselective synthesis of bis(E-2-bromovinyl) selenides and unsymmetrical E-2-bromovinyl selenides was developed based on the SeBr2 and PhSeBr transfer reactions which proceeded with higher selectivity compared to analogous addition reactions of SeBr2 and PhSeBr to alkynes under the same conditions.

scholarly journals Synthesis of Network Polymers by Means of Addition Reactions of Multifunctional-Amine and Poly(ethylene glycol) Diglycidyl Ether or Diacrylate Compounds

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2047
Author(s):  
Naofumi Naga ◽  
Mitsusuke Sato ◽  
Kensuke Mori ◽  
Hassan Nageh ◽  
Tamaki Nakano
Keyword(s):  
Ethylene Glycol ◽  
Room Temperature ◽  
Addition Reaction ◽  
Monomer Concentration ◽  
Diglycidyl Ether ◽  
Porous Polymers ◽  
Addition Reactions ◽  
Poly Ethylene Glycol ◽  
Network Polymers ◽  
Poly Ethylene

Addition reactions of multi-functional amine, polyethylene imine (PEI) or diethylenetriamine (DETA), and poly(ethylene glycol) diglycidyl ether (PEGDE) or poly(ethylene glycol) diacrylate (PEGDA), have been investigated to obtain network polymers in H2O, dimethyl sulfoxide (DMSO), and ethanol (EtOH). Ring opening addition reaction of the multi-functional amine and PEGDE in H2O at room temperature or in DMSO at 90 °C using triphenylphosphine as a catalyst yielded gels. Aza-Michael addition reaction of the multi-functional amine and PEGDA in DMSO or EtOH at room temperature also yielded corresponding gels. Compression test of the gels obtained with PEI showed higher Young’s modulus than those with DETA. The reactions of the multi-functional amine and low molecular weight PEGDA in EtOH under the specific conditions yielded porous polymers induced by phase separation during the network formation. The morphology of the porous polymers could be controlled by the reaction conditions, especially monomer concentration and feed ratio of the multi-functional amine to PEGDA of the reaction system. The porous structure was formed by connected spheres or a co-continuous monolithic structure. The porous polymers were unbreakable by compression, and their Young’s modulus increased with the increase in the monomer concentration of the reaction systems. The porous polymers absorbed various solvents derived from high affinity between the polyethylene glycol units in the network structure and the solvents.

scholarly journals Time-Resolved Spectroscopic Study of N,N-Di(4-bromo)nitrenium Ions in Selected Solutions

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3182 ◽  
Author(s):  
Lili Du ◽  
Xin Lan ◽  
Zhiping Yan ◽  
Ruixue Zhu ◽  
David Phillips
Keyword(s):  
Transient Absorption ◽  
Direct Detection ◽  
Reaction Pathway ◽  
Addition Reactions ◽  
Time Resolved ◽  
Nitrenium Ions ◽  
Future Studies ◽  
Nitrenium Ion ◽  
Design Time

Nitrenium ions are important reactive intermediates in chemistry and biology. In this work, femtosecond and nanosecond transient absorption (fs-TA and ns-TA) along with nanosecond time-resolved resonance Raman (ns-TR3) experiments were employed to examine the photochemical pathways of N-(4,4′-dibromodiphenylamino)-2,4,6-trimethylpyridinium BF4− (salt (DN) from just absorption of a photon of light to the production of the important N,N-di(4-bromophenyl)nitrenium ion 2. In acetonitrile (MeCN), the formation of halogenated diarylnitrenium ion 2 was observed within 4 ps, showing the vibrational spectra with strong intensity. The nucleophilic adduct reaction of ion 2 with H2O was also examined in aqueous solutions. The direct detection of the unique ortho adduct intermediate 3 shows that there is an efficient and exclusive reaction pathway for 2 with H2O. The results shown in this paper give new characterization of 2, which can be used to design time-resolved spectroscopy investigations of covalent addition reactions of nitrenium ions with other molecules in future studies.

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