A mechanistic study of the addition of alkynes to Brook silenes

2009 ◽  
Vol 87 (1) ◽  
pp. 307-313 ◽  
Author(s):  
Kaarina K Milnes ◽  
Kim M Baines
Keyword(s):  
Reaction Mechanism ◽  
Cycloaddition Reaction ◽  
Convincing Evidence ◽  
Membered Ring ◽  
Mechanistic Study ◽  
Mechanistic Probe

The addition of the alkyne-containing mechanistic probes (trans-2-phenylcyclopropyl)ethyne, (trans,trans-2-methoxy-3-phenylcyclopropyl)ethyne, and (trans,trans-2-methoxy-1-methyl-3-phenylcyclopropyl)ethyne (1a–1c) to a Brook silene 2-(1-adamantyl)-2-trimethylsiloxy-1,1-bis(trimethylsilyl)-1-silene (14) was examined. When alkyne 1a was added to the silene, an ene adduct was observed; however, addition of alkyne 1c to 14 gave a mixture of silacyclo butenes and silacycloheptenes. The regiochemistry of the phenyl and methoxy substituents on the seven-membered ring of the silacycloheptenes provides convincing evidence for the formation of a biradical intermediate along the reaction pathway.Key words: Brook silene, alkyne, cycloaddition, reaction mechanism, mechanistic probe.

The addition of alkynes to a tetrasilyldisilene — Evidence for a biradical intermediate

2005 ◽  
Vol 83 (9) ◽  
pp. 1568-1576 ◽  
Author(s):  
Stephen E Gottschling ◽  
Michael C Jennings ◽  
Kim M Baines
Keyword(s):  
Reaction Mechanism ◽  
Key Words ◽  
Cycloaddition Reaction ◽  
Major Product ◽  
Convincing Evidence ◽  
Mechanistic Probe

The addition of two newly developed mechanistic probes, (trans,trans-2-methoxy-3-phenylcyclopropyl)ethyne (1) and (trans,trans-2-methoxy-1-methyl-3-phenylcyclopropyl)ethyne (2), to tetrakis(tert-butyldimethylsilyl)disilene (3) has been investigated. The addition of 1 to 3 gave 1-[2-(cis-2-methoxy-3-phenylcyclopropylidene)vinyl]-1,1,2,2-tetrakis(tert-butyldimethylsilyl)disilane (5) as the major product; whereas addition of alkyne 2 to the disilene gave three stereoisomers of 1,1,2,2-tetrakis(tert-butyldimethylsilyl)-6-methoxy-5-methyl-7-phenyl-1,2-disilacyclohepta-3,4-diene (7–9) and 1,1,2,2- tetrakis(tert-butyldimethylsilyl)-3-(trans,trans-2-methoxy-1-methyl-3-phenylcyclopropyl)-1,2-disilacy-clobut-3-ene (10) as the major products. The formation of cycloheptaallenes 7–9 provides convincing evidence that the addition of alkynes to tetrasilyldisilenes involves the formation of a biradical intermediate. Key words: disilene, alkyne, cycloaddition, reaction mechanism, mechanistic probe.

Vinyl ether hydrolysis. XVII. Oxacyclonon-2,8-diene and the question of the unorthodox reaction mechanism for 9-methoxyoxacyclonon-2-ene

1984 ◽  
Vol 62 (1) ◽  
pp. 74-76 ◽  
Author(s):  
R. A. Burt ◽  
Y. Chiang ◽  
A. J. Kresge ◽  
S. Szilagyi
Keyword(s):  
Reaction Mechanism ◽  
Vinyl Ether ◽  
Membered Ring ◽  
Specific Rate ◽  
Ether Group ◽  
Reaction Proceeds ◽  
Great Reactivity ◽  
Rate Of Hydrolysis ◽  
Acid Catalyzed ◽  
Hydrolysis Of

The acid-catalyzed hydrolysis of the nine-membered ring cyclic vinyl ether, oxacyclonon-2,8-diene, occurs with a normal isotope effect, [Formula: see text], which indicates that this reaction proceeds by the conventional vinyl ether hydrolysis mechanism involving rate-determining proton transfer to carbon. The specific rate of this reaction, [Formula: see text], may then be used to show that there is no significant ring-size effect on the rate of hydrolysis of a vinyl ether group in a nine-membered ring. The previously noted unusually great reactivity of the vinyl ether group in 9-methoxyoxacyclonon-2-ene, for which an unorthodox reaction mechanism has been claimed, must therefore be due to some other cause.

Copper hydride-mediated electrophilic amidation of vinylarenes with dioxazolones – a computational mechanistic study

2019 ◽  
Vol 48 (38) ◽  
pp. 14337-14346
Author(s):  
Sven Tobisch
Keyword(s):  
Mechanistic Study ◽  
Copper Hydride ◽  
Mechanistic Probe ◽  
Mechanistic View

An in-depth computational mechanistic probe of the CuH-mediated formal hydroamidation of vinylarenes with dioxazolones allowed the substitution of mechanistic hypothesis advanced previously by a computationally verified mechanistic view.

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.

Insights into the cycloaddition reaction mechanism between ketenimine and unsaturated hydrocarbon: A theoretical study

2016 ◽  
Vol 90 (5) ◽  
pp. 1027-1033 ◽  
Author(s):  
Wenxing He ◽  
Hong Zhang ◽  
Nana Wang ◽  
Xiaojun Tan ◽  
Weihua Wang ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Theoretical Study ◽  
Cycloaddition Reaction ◽  
Unsaturated Hydrocarbon

Theoretical study on the cycloaddition reaction mechanism between ketenimine and acetonitrile

2016 ◽  
Vol 15 (3) ◽  
pp. 221-230 ◽  
Author(s):  
Wenxing He ◽  
Weihua Wang ◽  
Xiaojun Tan ◽  
Ping Li
Keyword(s):  
Reaction Mechanism ◽  
Theoretical Study ◽  
Cycloaddition Reaction

ChemInform Abstract: Highly Stereoselective 7-Membered Ring Synthesis Based upon the Oxidopyrylium-Alkene [5 + 2] Cycloaddition Reaction.

ChemInform ◽  
2010 ◽  
Vol 33 (6) ◽  
pp. no-no
Author(s):  
Naoki Ohmori ◽  
Toru Miyazaki ◽  
Satoshi Kojima ◽  
Katsuo Ohkata
Keyword(s):  
Cycloaddition Reaction ◽  
Membered Ring ◽  
Ring Synthesis

scholarly journals An ab initio study of the mechanism of formation of a silicic bis-heterocyclic compound from silylenesilylene (H2Si=Si:) and ethene

2012 ◽  
Vol 77 (1) ◽  
pp. 75-81
Author(s):  
Xiuhui Lu ◽  
Leyi Shi ◽  
Yongqing Li ◽  
Zhina Wang
Keyword(s):  
Potential Energy ◽  
Heterocyclic Compound ◽  
Singlet State ◽  
Reaction Pathway ◽  
Cycloaddition Reaction ◽  
Membered Ring ◽  
Energy Profile ◽  
Ab Initio Study ◽  
Mechanism Of Formation ◽  
Potential Energy Profile

The mechanism of the cycloaddition reaction of the formation of a silicic bis-heterocyclic compound between singlet state silylenesilylene (H2Si=Si:) and ethene wasi investigated by the CCSD(T)//MP2/6-31G* method. From the potential energy profile, it can be predicted that the reaction has one dominant reaction pathway. The presented rule of the dominant reaction pathway is that the [2+2] cycloaddition effect of the two reactants leads to the formation of a four-membered ring silylene (INT1). When the four-membered ring silylene (INT1) interacts with ethene, due to sp3 hybridization of the Si: atom in four-membered ring silylene (INT1), the four-membered ring silylene (INT1) further combines with ethene to form a silicic bis-heterocyclic compound (P2).

Sign in / Sign up

Export Citation Format

Share Document