Spiro octa-4,6-diene

Pirkle, W. H. Smith, S. G. Koser, G. F. Stereospecificity and wavelength dependence in the photochemical rearrangement of spiro[2.5]octa-4,7-dien-6-ones to quinone methides. j. Am. Chem. Soc. 1969, 91, 1580-1582. 

Schuster, D. I. Krull, I. S. Photochemistry of unsaturated ketones in solution. XIX. Photochemistry of spiro[2.5]octa-4,7-dien-6-one. 2. Mechanistic aspects and the relationship to the photochemistry of quinone methides. Mol. Photochem. 1969, 1, 107-133. 

C2PSi-C2N2Si-C6 5,8-Diaza-l-phospha-4-sila-benzo-spiro[3.4]octa-2,6-diene 6, 681/... 

Comparison with the reported reactivity of the spiro[2.5]octa-l,4-dien-3-one 110 and 4-(hexafluoroisopropylidene)cyclohexa-2,4-dien-l-one 111 have suggested that the conjugated cyclopropane ring of compounds 108 and 109 imparts a strong acid dependence to its reactivity with nucleophiles, Eq. (45). This property is likely to be relevant for the exceptional reactivity of these antibiotics toward DNA [148]. 

D 6-Benzyl-1,1-dideutero-5,8-dimethoxy-6-methyl-4,7-diaza-spiro[2.5 octa-4,7-dien 55 46 3... 

A convenient route to the tetrahydropentalenes 109 and 110 has been discovered through pyrolysis of spiro [ 3.4]octa-5,7-diene.161 ... 

Bicyclo 5.1.0]octa-2,5-dien-<8-spiro-5)-cyclopentadien -1,2,3,4-Te-trachlor- V/Id, 391 f. 

In an analogous manner, treatment of 4-(2-haloethyl)-phenols and -l-naphthols " with bases produces spiro[2.5]octa-4,7-dien-6-ones and their benzo analogues, respectively. The basic treatments of jS-oxiranyl ketones , esters (equation 13) , nitriles , sulfones and alkynes affords 2-(hydroxymethyl) cyclopropyl derivatives, usually as the sole cyclization product. The cyclization occurs regiospecifically by the intramolecular attack of the anion on the y-carbon in the oxirane ring. Attack of the anion on the 5-carbon in the oxirane, which should lead to the formation of cyclobutanols, usually does not take... 

An exceptional case of substitution-initiated cyclopropanation is found in the formation of 21. Winstein and Baird have studied Arj -3-participation in the cyclization reactions of 4-hydroxyphenyl derivatives. 2-(4-Hydroxyphenyl)ethyl bromide reacts via ion 19 with an excess of sodium methoxide in methanol at a rate which is initially 1000 times faster than that of 2-(4-methoxyphenyl)ethyl bromide. Evidently the dienone, spiro[2.5]octa-l,4-dien-3-one (20) is formed, but it reacts rapidly with methoxide ion to give the product 21. However, under modified conditions the spiro compound 20 can be isolated. ... 

In a study towards the synthesis of the tricarbonyliron complex of 8-methylenespiro[2.5]octa-4,6-diene 52 starting from spiro[2.5]octa-4,6-diene (49), conversion of its tricarbonyliron complex 50 via hydride abstraction, nucleophilic addition of hydroxide and oxidation gave the spiro[2.5]octa-5,7-dien-4-one-tricarbonyliron complex 51, which, however, could not be converted to the target complex 52 via Wittig olefination. An alternative approach to generate a Wittig reagent from spiro[2.5]octa-4,6-diene (49) via conversion to a phosphonium system 53 was likewise unsuccessful. ... 

Flash-vacuum pyrolysis of spiro[2.5]octa-4,6-diene-tricarbonyliron complex 57 gave the free ligand 58 in 53% yield accompanied by ring-opened products, while the analogous 7-methylene and 7-ethylidene complexes of 57 did not give the unchanged free ligand under the same conditions. ... 

Similarly, no free spiro[2.5]octa-5,7-dien-4-one was obtained under flash-vacuum pyrolysis conditions applied to its complex 51. ... 

Oxo-bicyclo[5.1,0]octa-2,4-dicne)-tricarbonyl- 1858, 1940 (8-OxO Spiro[2.5]octa-4,6-diene)-lri-carbonyl- 1861 C,.H N,... 

Cyclopropan- 1101... 

Cyclopropan-[Pg.3521]

Cyclopropan--[Pg.3522]

Borata-bicydo[3.3.1]nonan-<9-spiro-4>-3-hydro-<6,7-beiizo-3-oxoiiia-l-azonia-5-aza-2,4-[Pg.836]

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