Generation of a m-xylylene derivative and formation of a 2,2-metacyclophane

Gajewski, Joseph J.; Chang, Ming Jing; Stang, Peter J.; Fisk, Thomas E.

doi:10.1021/ja00526a060

Cited by 20 publications

(17 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…m-Quinodimethane, the parent hydrocarbon of either the m-quinonoid or dimethyl-substituted m-quinodimethane, is also known to dimerize in an intermolecular double head-to-head fashion under the formation of m-cyclophane. [20] In benzene, 4 m…”

Section: Angewandte Chemiementioning

confidence: 99%

CAAC‐Based Thiele and Schlenk Hydrocarbons

et al. 2020

View full text Add to dashboard Cite

Diradicals have been of tremendous interest for over a century ever since the first reports of p‐ and m‐phenylene‐bridged diphenylmethylradicals in 1904 by Thiele and 1915 by Schlenk. Reported here are the first examples of cyclic(alkyl)(amino)carbene (CAAC) analogues of Thiele's hydrocarbon, a Kekulé diradical, and Schlenk's hydrocarbon, a non‐Kekulé diradical, without using CAAC as a precursor. The CAAC analogue of Thiele's hydrocarbon has a singlet ground state, whereas the CAAC analogue of Schlenk's hydrocarbon contains two unpaired electrons. The latter forms a dimer, by an intermolecular double head‐to‐tail dimerization. This straightforward synthetic methodology is modular and can be extended for the generation of redox‐active organic compounds.

show abstract

Section: Angewandte Chemiementioning

confidence: 99%

CAAC‐Based Thiele and Schlenk Hydrocarbons

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Kinetic analysis of the decomposition of 36a leading to toluene as the main product gave an E a value of 156.7 kJ mol À1 . 4 [45], followed by the studies of the groups of Goldblatt and Hawkins in the 1940s and 1950s, respectively [46 -53], until the extensive kinetic studies of Riistima and Harva, and Gajewski et al [54] [55], these mechanistic studies are still up to date [29] [56]. This may be due to the fact that this reaction network remains challenging because of the cooccurrence of the three major reactions of the VCB system in 4 shown in Table 3 leading to rate equations with feedback routes.…”

Section: Isomerizations Related Tomentioning

confidence: 99%

“…In Scheme 10, the products arising from the pyrolysis of 4 are shown. Racemization of 4 occurred in both gaseous and liquid phase at ambient and reduced pressure [45] [55]. Remarkably, performing the reaction in a flow apparatus using supercritical EtOH as solvent, no racemization was observed [57] [58].…”

Section: Isomerizations Related Tomentioning

confidence: 99%

“…The formation of dipentene is a consequence of the biradical 38 the reaction passes through. Due to resonance stabilization of one radical position a mirror plane is generated (C s symmetry) leading to racemic (AE)-40 [55] [65]. Hence, pyrolysis in supercritical EtOH yielded racemic 40 without racemization of the starting material [57] [58], a prior racemization of 4 does not seem to be the reason for the dipentene formation.…”

Section: Isomerizations Related Tomentioning

confidence: 99%

See 1 more Smart Citation

Thermal Rearrangements of Monoterpenes and Monoterpenoids

Stolle¹,

Ondruschka²,

Hopf³

2009

Helvetica Chimica Acta

View full text Add to dashboard Cite

On the occasion of the 70th anniversary of the Nobel Prize in Chemistry awarded to Leopold Ružička for his work on polymethylenes and higher terpenes 1 )The thermal conversions of monoterpenes and monoterpenoids are an interesting field of research with respect to mechanistic, kinetic, and theoretical issues. Since the beginning of the 20th century, these reactions have attracted the interest of many research groups, and even today there are sufficient problems and questions to deal with. This review covers the thermal isomerization chemistry of pinanes, pinenes, carenes, and thujenes over the past 70 years. Categorization of these compounds into groups, each of them being represented by a small parent molecule (cyclobutane, vinylcyclobutane, vinylcyclopropane), allows systematization of multitude of publications.

show abstract

“…20 times faster than the rearrangement. [21] 1-Isopropenyl-4,7-dioxaspiro[2.4]heptane (8 ·؉ ) is electronically equivalent to a dimethoxy-substituted vinylcyclopropane, but with fewer degrees of conformational freedom. As a single methoxyl group is already highly cation stabilizing, it is not surprising that 8 ·؉ also undergoes barrierless ring opening, as is indicated by the computed C1ϪC3 distance of 2.36 Å .…”

Section: Methodsmentioning

confidence: 99%

Substituent Effects in the Vinylcyclopropane Radical Cation Rearrangement: A Computational Road to a New Synthetic Tool

Oxgaard

Wiest

2003

Eur J Org Chem

View full text Add to dashboard Cite

The effect of substituents on the rearrangement of vinylcyclopropane radical cation to cyclopentene was explored by density functional theory. Correlations have been established between the activation energy of the system and the nature, as well as the position, of the substituents. It was found that radical-or cation-stabilizing substituents in select positions reduce the activation energy for the rearrangement substantially, while activation energies for competing hydrogen shifts were largely left unchanged. We have identified positions in the vinylcyclopropane where substitution is necessary, and others that can be substituted less discriminately.

show abstract

Generation of a m-xylylene derivative and formation of a 2,2-metacyclophane

Cited by 20 publications

References 0 publications

CAAC‐Based Thiele and Schlenk Hydrocarbons

CAAC‐Based Thiele and Schlenk Hydrocarbons

Thermal Rearrangements of Monoterpenes and Monoterpenoids

Substituent Effects in the Vinylcyclopropane Radical Cation Rearrangement: A Computational Road to a New Synthetic Tool

Contact Info

Product

Resources

About