scholarly journals Challenges in the Highly Selective [3 + 1]-Cycloaddition of an Enoldiazoacetamide to Form a Donor–Acceptor Cis-Cyclobutenecarboxamide

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3520
Author(s):  
Sipak Joyasawal ◽  
Donghui Ma ◽  
Michael P. Doyle
Keyword(s):  
Low Temperature ◽  
Ring Opening ◽  
Cycloaddition Reaction ◽  
Methyl Substituent ◽  
Donor Acceptor

A substituted donor–acceptor cyclobutenecarboxamide is synthesized with modest enantiocontrol through a chiral copper(I) complex catalyzed [3 + 1]-cycloaddition reaction of α-acyl diphenylsulfur ylides with 3-siloxy-2-diazo-3-butenamides. With a methyl substituent on the 4-position of the 3-butenamide, the cis-vicinal-3,4-disubstituted cyclobutenecarboxamide is formed with >20:1 diastereocontrol. Donor-acceptor 3-methyl-2-siloxycyclopropenecarboxamide is rapidly formed from the reactant enoldiazoamide and undergoes catalytic ring opening to give only the Z-γ-substituted metallo-enolcarbene. Elimination from 3-siloxy-2-diazo-3-pentenamide to form the conjugated 3-siloxy-2,4-pentadienamide is competitive but minimized at low temperature.

Donor–Acceptor Cyclopropane Ring Opening with 6-Amino-1,3-dimethyluracil and Its Use in Pyrimido[4,5-b]azepines Synthesis

2021 ◽  
Author(s):  
Anna E. Vartanova ◽  
Irina I. Levina ◽  
Victor B. Rybakov ◽  
Olga A. Ivanova ◽  
Igor V. Trushkov
Keyword(s):  
Ring Opening ◽  
Cyclopropane Ring ◽  
Donor Acceptor

A donor–acceptor conjugated block copolymer of poly(arylenevinylene)s by ring-opening metathesis polymerization

2015 ◽  
Vol 51 (44) ◽  
pp. 9113-9116 ◽  
Author(s):  
Shu-Wei Chang ◽  
Masaki Horie
Keyword(s):  
Block Copolymer ◽  
Ring Opening ◽  
Ring Opening Metathesis Polymerization ◽  
Metathesis Polymerization ◽  
Donor Acceptor

A donor–acceptor conjugated block copolymer of poly(arylenevinylene)s has been synthesized by ring-opening metathesis polymerization.

Ring-opening reactions of donor–acceptor cyclopropanes with cyclic ketals and thiol ketals

2020 ◽  
Vol 18 (33) ◽  
pp. 6492-6496 ◽  
Author(s):  
Dongxin Zhang ◽  
Lei Yin ◽  
Junchao Zhong ◽  
Qihang Cheng ◽  
Hu Cai ◽  
...  
Keyword(s):  
Ring Opening ◽  
Ring Opening Reactions ◽  
Donor Acceptor

Cyclic (thiol) ketals were used as hetero-nucleophiles for the ring opening of donor–acceptor cyclopropanes to afford functionalized diethers.

scholarly journals Low-temperature and purification-free stereocontrolled ring-opening polymerisation of lactide in supercritical carbon dioxide

2020 ◽  
Vol 22 (7) ◽  
pp. 2197-2202 ◽  
Author(s):  
Simon P. Bassett ◽  
Andrew D. Russell ◽  
Paul McKeown ◽  
Isabel Robinson ◽  
Thomas R. Forder ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Low Temperature ◽  
Supercritical Carbon Dioxide ◽  
Ring Opening ◽  
Solvent Free ◽  
Free Ring ◽  
First Time ◽  
Supercritical Carbon

A stereoselective, solvent-free ring-opening polymerisation (ROP) of lactide (LA) in supercritical carbon dioxide (scCO2) is reported for the first time.

scholarly journals Synthesis of 5-Azaindoles via a Cycloaddition Reaction between Nitriles and Donor−Acceptor Cyclopropanes

2010 ◽  
Vol 12 (14) ◽  
pp. 3168-3171 ◽  
Author(s):  
Mahmoud M. Abd Rabo Moustafa ◽  
Brian L. Pagenkopf
Keyword(s):  
Cycloaddition Reaction ◽  
Donor Acceptor

Catalytic Asymmetric Transformations of Racemic Aziridines

Synthesis ◽  
2020 ◽  
Vol 52 (12) ◽  
pp. 1738-1750 ◽  
Author(s):  
Zhuo Chai
Keyword(s):  
Ring Opening ◽  
Kinetic Resolution ◽  
Short Review ◽  
Asymmetric Transformations ◽  
Parallel Kinetic Resolution ◽  
Donor Acceptor ◽  
Molecular Architectures ◽  
Catalytic Asymmetric ◽  
Asymmetric Transformation ◽  
Asymmetric Ring Opening

The catalytic asymmetric ring-opening transformations of aziridines represent an important strategy for the construction of various chiral nitrogen-containing molecular architectures. This short review covers the progress achieved in the catalytic asymmetric transformation of racemic aziridines, focusing on the catalytic strategies employed for each different type of such aziridines.1 Introduction2 Reaction of Racemic 2-Vinylaziridines3 Reaction of Racemic 2-Alkylaziridines3.1 Regiodivergent Parallel Kinetic Resolution3.2 Kinetic Resolution4 Reaction of Racemic 2-(Hetero)arylaziridines4.1 Kinetic Resolution4.2 Enantioconvergent Transformation5 Reaction of Racemic Donor–Acceptor-Type Aziridines6 Conclusion and Outlook

scholarly journals Lewis Acid Catalyzed Ring-Opening 1,3-Aminothiolation of Donor–Acceptor Cyclopropanes Using Sulfenamides

2020 ◽  
Vol 22 (6) ◽  
pp. 2276-2280 ◽  
Author(s):  
Avishek Guin ◽  
Thukaram Rathod ◽  
Rahul N. Gaykar ◽  
Tony Roy ◽  
Akkattu T. Biju
Keyword(s):  
Lewis Acid ◽  
Ring Opening ◽  
Donor Acceptor ◽  
Acid Catalyzed

scholarly journals Ab initio study of mechanism of forming a Si-heterocyclic spiro-Sn-heterocyclic ring compound by cycloaddition reaction of Me2Si=Sn: and ethene

2019 ◽  
Vol 44 (2) ◽  
pp. 114-121
Author(s):  
Xiaojun Tan ◽  
Xiuhui Lu
Keyword(s):  
Singlet State ◽  
Cycloaddition Reaction ◽  
Chemical Species ◽  
Heterocyclic Ring ◽  
Basis Set ◽  
Cycloaddition Reactions ◽  
Unoccupied Orbital ◽  
Donor Acceptor ◽  
Moller Plesset ◽  
First Time

X2Si=Sn: (X = H, Me, F, Cl, Br, Ph, Ar, etc.) are a new chemical species. The cycloaddition reactions of X2Si=Sn: are a new field of stannylene chemistry. The mechanism of the cycloaddition reaction between singlet state Me2Si=Sn: and ethene has been investigated for the first time here using second-order Møller-Plesset perturbation theory together with the 6-311++G** basis set for C, H and Si atoms and the LanL2dz basis set for Sn atoms. From the potential energy profile, it could be predicted that the reaction has one dominant reaction channel. The reaction process presented is that the 5p unoccupied orbital of Sn in Me2Si=Sn: and the π orbital of ethene form a π → p donor–acceptor bond resulting in the formation of an intermediate. The instability of this intermediate makes it isomerize to a four-membered Si-heterocyclic ring stannylene. Because the 5p unoccupied orbital of the Sn atom in the four-membered Si-heterocyclic ring stannylene and the π orbital of ethene form a π → p donor–acceptor bond, the four-membered Si-heterocyclic ring stannylene further combines with ethene to form another intermediate. Because the Sn atom in this intermediate assumes sp3 hybridization after the transition state, the intermediate isomerizes to a Si-heterocyclic spiro-Sn-heterocyclic ring compound. This result indicates the modes of cycloaddition reactions between X2Si=Sn: and symmetric π-bonded compounds, i.e. this study opens up a new field for stannylene chemistry.

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