Mechanistic Investigations into the Enantioselective Conia-Ene Reaction Catalyzed by Cinchona-Derived Amino Urea Pre-Catalysts and CuI

2013 ◽  
Vol 19 (42) ◽  
pp. 14286-14295 ◽  
Author(s):  
Filippo Sladojevich ◽  
Ángel L. Fuentes de Arriba ◽  
Irene Ortín ◽  
Ting Yang ◽  
Alessandro Ferrali ◽  
...  
2022 ◽  
Author(s):  
Bao Yu ◽  
mohamed selkti ◽  
Janick Ardisson ◽  
Marie-Isabelle Lannou ◽  
Geoffroy Sorin

A novel access to fused furan cores using silver oxide(I) has been developed. Mechanistic investigations would indicate the involvement of a Conia-ene reaction/radical cyclization for an expedient path to complex...


1996 ◽  
Vol 24 (4) ◽  
pp. 769-775
Author(s):  
Jing-Yao Zhou ◽  
Yu Jia ◽  
Qiu-Yi Shao ◽  
Shi-Hui Wu
Keyword(s):  

2018 ◽  
Author(s):  
Tanner C. Jankins ◽  
Robert R. Fayzullin ◽  
Eugene Khaskin

We report a one-step, Ru(II)-catalyzed cyclopropanation reaction that is conceptually different from the previously reported protocols that include Corey-Chaykovsky, Simmons-Smith, and metal catalyzed carbene attack on olefins. Under the current protocol, various alcohols are transformed into sulfone substituted cyclopropanes with excellent isolated yields and diastereoselectivities. This new reaction forms highly congested cyclopropane products with three new C–C bonds, three or two new chiral centers and one new quaternary carbon center. 22 examples of isolated substrates are given. Previously reported synthetic routes for similar substrates are all multi-step, linear routes that proceed with overall low yields and poor control of stereochemistry. Experimental mechanistic investigations suggest initial metal-catalyzed dehydrogenation of the alcohol substrate and catalyst independent stepwise attack of two equivalents of sulfone on the aldehyde under basic conditions. While the Ru(II) is only responsible for the initial dehydrogenation step, the rate of aldehyde formation is crucial to maintaining the right balance of intermediates needed to afford the cyclopropane product.


2019 ◽  
Author(s):  
Benjamin Lipp ◽  
Lisa Marie Kammer ◽  
Murat Kucukdisli ◽  
Adriana Luque ◽  
Jonas Kühlborn ◽  
...  

Simultaneous sulfonylation/arylation of styrene derivatives is achieved in a photoredox-catalyzed three-component reaction using visible light. A broad variety of difunctionalized products is accessible in mostly excellent yields and high diastereoselectivity. The developed reaction is scalable and suitable for the modification of styrene-functionalized biomolecules. Mechanistic investigations suggest the transformation to be operating through a designed sequence of radical formation and radical combination.<br>


2017 ◽  
Vol 90 (3) ◽  
pp. 550-561 ◽  
Author(s):  
Prithwiraj Mandal ◽  
Siva Ponnupandian ◽  
Soumyadip Choudhury ◽  
Nikhil K. Singha

ABSTRACT Thiol-ene modification of high vinyl content thermoplastic elastomeric styrene butadiene styrene (SBS) block copolymer (BCP) was carried out using different thiolating agents in toluene at 70 °C. 1H NMR analysis confirmed the participation of vinyl double bond in the thiol-ene modification reaction of SBS. Surface morphology of the block copolymers evaluated by atomic force microscopy analysis showed higher roughness after the thiol-ene reaction. The thiol-modified SBS block copolymer showed better adhesion strength and oil resistance properties than the pristine SBS.


2021 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Laura Brelle ◽  
Estelle Renard ◽  
Valerie Langlois

A novel generation of gels based on medium chain length poly(3-hydroxyalkanoate)s, mcl-PHAs, were developed by using ionic interactions. First, water soluble mcl-PHAs containing sulfonate groups were obtained by thiol-ene reaction in the presence of sodium-3-mercapto-1-ethanesulfonate. Anionic PHAs were physically crosslinked by divalent inorganic cations Ca2+, Ba2+, Mg2+ or by ammonium derivatives of gallic acid GA-N(CH3)3+ or tannic acid TA-N(CH3)3+. The ammonium derivatives were designed through the chemical modification of gallic acid GA or tannic acid TA with glycidyl trimethyl ammonium chloride (GTMA). The results clearly demonstrated that the formation of the networks depends on the nature of the cations. A low viscoelastic network having an elastic around 40 Pa is formed in the presence of Ca2+. Although the gel formation is not possible in the presence of GA-N(CH3)3+, the mechanical properties increased in the presence of TA-N(CH3)3+ with an elastic modulus G’ around 4200 Pa. The PHOSO3−/TA-N(CH3)3+ gels having antioxidant activity, due to the presence of tannic acid, remained stable for at least 5 months. Thus, the stability of these novel networks based on PHA encourage their use in the development of active biomaterials.


ACS Catalysis ◽  
2021 ◽  
pp. 9485-9494
Author(s):  
Logan E. Vine ◽  
Ryan D. Reeves ◽  
Eleanor M. Landwehr ◽  
Israel Fernández ◽  
Jennifer M. Schomaker

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