摘要:

Thermolysis of 2,2,6,7‐Tetramethyl‐1,7‐epidioxybicyclo[4.3.0]non‐8‐ene.Dye‐sensitized photooxygenation of the cyclopentadiene derivative1gives three products: the peroxide2aand the monocyclic ketones5and8. 5and8are probably formed by rearrangement of the unstable peroxide2b. Thermolysis of2agives, besides5and8, the furylketone9and the cyclooctenone derivative10. The structures of the new compounds have been established by means of spectroscopic methods and chemical transformations. A reaction mechanism for the formation of5, 8, 9and10from2ais proposed. Irradiation of10leads to the two diastereoisomerictranscyclooctenon

ISSN:0018-019X    

DOI:10.1002/hlca.19760590102

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractA comparison of the reactivity of ene‐sulfides and en‐ethers towards organometallic reagents reveals some remarkable differences. With the thio compounds metallation at the olefinic site next to the hetero atom dominates clearly over the alternative deprotonation of an allylic position. Only with propenyl phenyl sulfide both exchange modes were observed simultaneously, whereas with all higher homologues of it as well as vinyl phenyl sulfide the metal was exclusively attached to the olefinic α‐carbo

ISSN:0018-019X    

DOI:10.1002/hlca.19760590103

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

Synthese und Eigenschaften von 3,7‐Dehydrotroponen7‐exo‐Brom‐7‐endo‐t‐butyl‐(9) und 7‐exo‐Chlor‐7‐endo‐phenyl‐bicyclo[3.2.0]hept‐2‐en‐6‐on(12) sowie 7,7‐Dichlor‐2,3‐benzo‐bicyclo[3.2.0]hept‐2‐en‐6‐on (16), das letztere hergestellt aus Dichlorketen und Inden (15), wurden mit 1 Moläquiv. N‐Bromsuccinimid behandelt. Die entsprechenden Hauptprodukte waren 4‐exo‐, 7‐exo‐Dibrom‐7‐endo‐t‐butyl‐(10) und 4‐exo‐Brom‐7‐exo‐chlor‐7‐endo‐phenyl‐bicyclo[3.2.0]hept‐2‐en‐6‐on (13) sowie 4‐exo‐Brom‐7, 7‐dichlor‐2, 3‐benzo‐bicyclo[3.2.0] hept2‐en‐6‐on (17). Neben dieser « normalen » Bromierung fand in zwei Fällen eine solche unter Allylisomerisierung statt: Als Nebenprodukt bei der Monobromierung von12wurde 4‐exo‐Brom‐6‐exo‐chlor‐6‐endo‐phenyl‐bicyclo[3.2.0]hept‐2‐en‐7‐on (14) gebildet und bei der Dibromierung von9(wahrscheinlich via10) war das Hauptprodukt 2,4‐exo, 6‐exo‐Tribrom‐6‐endo‐t‐butyl‐bicyclo[3.2.0]hept‐2‐en‐7‐on (11).Aus der Behandlung der vier bromierten Bicycloheptenon‐Derivate10, 11und13sowie17mit 1,1 mol Triäthylamin bei tiefer Temperatur liessen sich 2‐t‐Butyl‐(5), 6‐Brom‐2‐t‐butyl‐(6) und 2‐Phenyl‐3, 7‐dehydrotropon(7) sowie 2‐Chlor‐4, 5‐benzo‐3, 7‐dehydro‐trop

ISSN:0018-019X    

DOI:10.1002/hlca.19760590104

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

Compounds of the 3,4‐dihydro‐ionone series as models for the photochemistry of γ, δ‐ and δ,ϵ‐ unsaturated ketones and aldehydes.The photochemistry of γ, δ‐ and δ,ϵ‐unsaturated carbonyl compounds of the dihydro‐ionone series has been studied, with special attention to the investigation of oxetane formationversushydrogen abstraction.UV.‐irradiation of the dihydro‐β‐ionone compounds with structureA(1,7,14,18,24,29) led to isomeric ethers with structuresB(2,8,15,19,25,30),C(3,9,16,20,26,31) andD(4,21,27), isomeric bicyclic alcohols with structureE(5,10,17,22,28), and photoreduction products with structureF(6,11,12,13). Photolysis of dihydro‐γ‐ionone (32) gave a complex mixture containing fragmentation product35, hydrocarbon36, β‐ambrinol (34), oxetane33, as well as dihydro‐β‐ionone (1) and three of its photoproducts (2,3,5). The dihydro‐α‐ionone compounds37and40gave mixtures of fragmentation products and the oxetanes38and41. Irradiation of the side‐chain homologues42and45yielded43, which photo‐cyclizes to44. In contrast,3,4‐dihydro‐3′,4′‐dehydro‐β‐ionone (46) gave merely the isomeric open‐chain triene‐ketone47.The structures assigned to the ethers2,3,33,38and to the alcohols5,10,13could be confirmed by chemical reactions and mutual interconversions. The structure of the ether21had to be established by X‐ray analysis, details of which are described.A novel intramolecular hydrogen transfer is involved in formation of ethersB. The photocyclizationA → Dprobably proceeds by addition of the carbonyl‐C atom to the double bond (A → h), followed by methyl (1 → 2)‐shift

ISSN:0018-019X    

DOI:10.1002/hlca.19760590105

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

New Ambra Odorants by Photoreactions of 15, 16‐Dinorlabd‐8(20)‐en‐13‐one.UV.‐irradiation of 15,16‐dinorlabd‐8(20)‐en‐13‐one (1) led to the fragmentation product4and its photo‐cyclisation product5. Ethers6and7and the βγ‐unsaturated alcohols8and10were formedviaketone9, a double bond isomer of1. The olfactory properties of the p

ISSN:0018-019X    

DOI:10.1002/hlca.19760590106

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

Photochemistry of α,β‐epoxy‐eucarvone.On π,π*‐excitation (λ = 254 nm)4isomerizes to the bicyclic ketoaldehyde5; on n,π*‐excitation (λ ⩾ 280 nm)4gives5, the β,γ‐unsaturated ketone6, the enone7and the cyclobutanone8. Scission of the (C—C)‐bond of the oxirane4would give the dihydrofuranee, which could isomerize to the ketoaldehyde5. On the other hand,4is assumed to isomerize to the β,γ‐unsaturated aldehydec, which could yield6and7by photodecarbonylation. The cyclo‐butanone8is shown to be a photoisomer of the ketone6.Furthermore, eucarvol (18) rearranges by a thermal [1,5]‐H‐shift to dihydro‐eucarvone (20); on UV.‐irradiat

ISSN:0018-019X    

DOI:10.1002/hlca.19760590107

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractA synthesis of twista‐4,9‐diene (17) from tricyclo[4.3.1.03,8]dec‐4‐en‐10‐one (2) i

ISSN:0018-019X    

DOI:10.1002/hlca.19760590108

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

Durch Erhitzen mit Bromwasserstoffsäure lassen sich aus Methyl (2Z)‐4‐Brom‐2‐brommethyl‐2‐butenoat (1) bzw. ‐2‐pentenoat (3) die Lactone 2‐Brommethyl‐2‐buten‐4‐olid (2) bzw. ‐2‐penten‐4‐olid (4) gewinnen. Unter den gleichen Bedingungen werden Methyl (2Z)‐und (2E)‐4, 4‐Dibrom‐2‐brommethyl‐2‐butenoat (5und6) nur zu den entsprechenden Säuren7und8hydrolysiert. Die (2Z)‐ resp. (2E)‐Konfiguration von7und8werden durch die folgenden (trans/cis>1)13C zu1H Kopplungen zwischen den an der Doppelbindung vicinal gelegenen Kohlenstoff‐ und Wasserstoffatomen im13C‐NMR.‐Spektrum bestätigt:13COO zu H—C(3) 5,7 Hz in7und 10,2 Hz in8;13CH2Br zu H—C(3) 8,7 Hz in7und 6,9 Hz in8.Mittels N‐Bromsuccinimid werden 2‐Buten‐4‐olid (10) bzw. sein 2‐Methylderivat12in 4‐Brom‐2‐buten‐4‐olid (11) bzw. sein 2‐Methylderivat13übergeführt. Mit Methanol entsteht aus134‐Methoxy‐2‐methyl‐2‐buten‐4‐olid (14). Die Bromierung von 2‐Penten‐4‐olid (15) oder von 3‐Penten‐4‐olid (16) unter denselben Bedingungen gibt hingegen 4,5‐Dibrom‐2‐penten‐4‐olid (17), während aus 2‐Brommethyl‐2‐pe

ISSN:0018-019X    

DOI:10.1002/hlca.19760590109

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractThe chemical ionization spectra of linear alkenes have been measured using H2O, CH4or CD3OD as ionizing gas. In the case of 1‐heptene the dependence of spectra on pressure, temperature and repeller field strength has been measured and is discusse

ISSN:0018-019X    

DOI:10.1002/hlca.19760590110

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractThe chemical ionization spectra of linear alkyl halides with up to nine carbon atoms have been studied using water as protonating agent. An alkyl ion with the same number of carbon atoms as the halide is produced. With more than six carbon atoms in the chain, fragmentation becomes important. The results show that excited hydronium ions participate as intermediates and the fragments of the resulting alkyl ions have branched structures.

ISSN:0018-019X    

DOI:10.1002/hlca.19760590111

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY