Photochemische Umwandlungen, 64. Die 3σ → 3π‐Route zu Oxepinen/Benzoloxiden

Prinzbach, Horst; Bingmann, H.; Markert, J.; Fischer, Gerhard W.; Knothe, Lothar; Eberbach, Wolfgang; Brokatzky-Geiger, J.

doi:10.1002/cber.19861190222

Cited by 35 publications

(5 citation statements)

References 128 publications

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“…Prinzbach and co-workers have discussed this aspect earlier and recently in detail. 9,14,30 At this point we note that the publication of an easy, multigram synthesis of only one valuable compound, namely cyclooctyne, by Brandsma and Verkruijsse in 197858 stimulated new developments in the field of…”

Section: Discussionmentioning

confidence: 99%

“…For instance, in most,9 but no in all,17 cases carbomethoxy groups lead to a decrease in kinetic stability; chlorine substituents have an even larger effect in the same direction in the nitrogen series,14 while trifluoromethyl groups exhibit a very small influence in oxaquadricyclanes. 9 The reaction rates are considerably increased when intramolecular cycloadditions are possible.9 These effects may be due to changes in the ground states of the strained tetracyclic compounds. The first step of the thermolysis can be considered to be highly exothermic (vide infra), so that the corresponding early transition states resemble the ground states.…”

Section: Spectroscopic and Structural Properties Of Heteroquadrlcyclanesmentioning

confidence: 99%

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3-Heteroquadricyclanes in organic synthesis

Tochtermann¹,

Olsson²

1989

Chem. Rev.

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Section: Discussionmentioning

confidence: 99%

Section: Spectroscopic and Structural Properties Of Heteroquadrlcyclanesmentioning

confidence: 99%

3-Heteroquadricyclanes in organic synthesis

Tochtermann¹,

Olsson²

1989

Chem. Rev.

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“…2 t 3-Bistrifluoromethyl-7-oxa-bicyclo [2.2.1]hepta-2,5-diene (5) (9) 4-methyI-10-oxa-4-aza-tricyclo[5.2.1.0 2 * 6 ]dec-8-ene-3,5-dione (6) (4) and exo-dicyclopentadiene (7) (10) were synthesized according to literature procedures, bicyclo[2.2.1]hept-2-ene (2-norbomene) (8) was used as received from Fluka. exo-3-(3,5-Dioxo-4-aza-tricycIo[5.2.1.0 2 > 6]dec-8-en-4-yl)-benzoic acid 1-phenyl-eth ester (V): 2.8 g (0.017 mol) cis-5-norbornene-exo-2,3-dicarboxylic anhydride were dissolved in 50 ml DMSO.…”

Section: -Yl)-benzoic Acid 1-phenyl-ethyl Ester (1) Exo-4-(3 T 5-dimentioning

confidence: 99%

Advanced Materials and Forms: Photosensitive Metathesis Polymers

Mühlebach

Schaedeli

1996

ACS Symposium Series

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The synthesis and ring opening metathesis homo-and copolymerization (ROMP) of the exo-7-oxa-norbornene-and exo-norbornene-carboximid esters, 1-3 and 1'-3' respectively, have been investigated. Molecular weights were controlled with 2-butene-l,4-diol as chain transfer agent. These homo-and copolymers were used to formulate very sensitive positive tone high resolution resists. They are the first positive working photoresists based on a metathesis polymer backbone.Cycloolefins with strained rings can be polymerized by the so called ROMP-reaction (= ring-opening-metathesis-polymerization) yielding linear chains with one double bond per repeat unit: Scheme 1. Whereas classical catalysts like WC1 6 /A1Et 2 C1 (1) have a very limited tolerance towards functional groups such as ketones, esters, amides and imides, and the recently discovered Schrock-type catalysts (Mo-and W-carbenes) (2) have a somewhat broader tolerance, certain ruthenium(II)-complexes allow the polymerization of almost any functionalized monomers even in aqueous or ethanolic solution. Scheme 1: Principle of the ring opening metathesis polymerization (ROMP).Therefore, polymers bearing almost any functional groups useful for specific applications can be designed. There is a fast increasing demand for speciality polymers for applications in many high technology fields. For example, homo-and copolymers containing specific acid cleavable side groups are used in today's chemically amplified positive tone photoresists (3). The excellent physical properties like high Tg-values and good thermostabilities of ROMP polymers derived from exo-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboximides (4) attracted our attention. Therefore we decided to synthesize specific exo-(7-oxa-)norbomene-carboximids with photochemically or thermally cleavable 0097-6156/96/0620-0364$12.00/0

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“…9 Unfortunately, all attempts to perform ring-opening metathesis polymerisation in water, employing the water soluble Grubbs catalyst…”

mentioning

confidence: 99%

“…Both pure 2-exo, 3-exo-7-oxanorbornene diol 1a and the corresponding endo isomer 1b were synthesized according to a literature procedure. 9 Unfortunately, all attempts to perform ring-opening metathesis polymerisation in water, employing the water soluble Grubbs catalyst RuCl 2 (NCHPh)-[Cy 2 PCH 2 CH 2 N(CH 3 ) 3 + Cl 2 ] 2 7 failed. Therefore, compounds 1a and 1b were transformed into their corresponding ketals 2a and 2b as reported by Schrock and co-workers.…”

mentioning

confidence: 99%

Carbohydrate analogue polymers by ring opening metathesis polymerisation (ROMP) and subsequent catalytic dihydroxylation

et al. 2001

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Ring opening metathesis poymerisation (ROMP) followed by catalytic dihydroxylation affords macromolecules with 1,2-diol structures. These new macromolecular compositions represent C-glycoside analogues of ribofuranose polymers that are thermally and hydrolytically stable.Carbohydrate-protein interactions play an important role in many biological processes. Polysulfates derived from carbohydrates were recognized as potent and selective inhibitors of the in vitro replication of HIV and other enveloped viruses. In the case of sulfated dextrans the activity strongly depended on the molar mass of the oligosaccharides. 1,2 The design of new carbohydrate-analogue polymers is of special interest in polymer chemistry and life sciences-applications range from drug systems to novel biocompatible materials and surface coatings. Ring-opening metathesis polymerisation (ROMP) offers attractive potential for the synthesis of well defined carbohydrate analogue polymers. The modern catalyst generations, developed by Schrock and Grubbs, tolerate polar groups and afford living polymerisation which is the key to molar mass control. Novel families of ROMP glycopolymers were prepared by Kiessling, Schrock, Grubbs and co-workers 3-7 using sugarsubstituted derivatives of norbornene and 7-oxanorbornenes as monomers. Since conventional polysaccarides are prone to metabolic degradation by glycosidases due to their glycosidic linkages, 2 hydrolytically stable carbohydrate-analogue compounds without glycoside linkages in the backbone represent interesting candidates for biomedical applications (Fig. 1).Here we present a versatile synthetic method for the preparation of novel polyribofuranose analogue polymers which do not contain glycoside linkages between the monomeric units in the polymer backbone that are prone to metabolic degradation by glycosidases. This should provide an oligosaccharide analogue structure with improved biocompatibility and longer half-life times. Initial research on related oligosaccharide-analogue polymers was reported by Clark and Lee 8 who used ROMP of 7-oxanorbornene diol derivatives. Since the double bonds of the polymer backbone were hydrogenated, the resulting saccharide-analogue polymers contained only two hydroxy groups per repeating unit. The objective of our research was the synthesis of polymers containing fully hydroxylated repeating units. These are pseudo-polyribofuranoses, with structures very similar to those of natural carbohydrates. The synthetic strategy displayed in Scheme 1 employs ROMP of dihydroxy-substituted bicyclic olefin monomers and subsequent dihydroxylation of the double bonds in the polymer backbone.Both pure 2-exo, 3-exo-7-oxanorbornene diol 1a and the corresponding endo isomer 1b were synthesized according to a literature procedure. 9 Unfortunately, all attempts to perform ring-opening metathesis polymerisation in water, employing the water soluble Grubbs catalyst RuCl 2 (NCHPh)-[Cy 2 PCH 2 CH 2 N(CH 3 ) 3 + Cl 2 ] 2 7 failed. Therefore, compounds 1a and 1b were transformed into their...

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Photochemische Umwandlungen, 64. Die 3σ → 3π‐Route zu Oxepinen/Benzoloxiden

Cited by 35 publications

References 128 publications

3-Heteroquadricyclanes in organic synthesis

3-Heteroquadricyclanes in organic synthesis

Advanced Materials and Forms: Photosensitive Metathesis Polymers

Carbohydrate analogue polymers by ring opening metathesis polymerisation (ROMP) and subsequent catalytic dihydroxylation

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