Diels-Alder reactions of cycloalkenones. 15. Synthesis of cis- and trans-.DELTA.6-4a-methyl-1-octalones

1989 ◽  
Vol 54 (5) ◽  
pp. 1217-1218 ◽  
Author(s):  
E. Charles Angell ◽  
Francesco Fringuelli ◽  
Ferdinando Pizzo ◽  
Lucio Minuti ◽  
Aldo Taticchi ◽  
...  
Keyword(s):  
Diels Alder ◽  
Cis And Trans

Products of reaction between styrene and some radicals with 2,2-diphenyl-1-picrylhydrazyl

1981 ◽  
Vol 59 (21) ◽  
pp. 3095-3104 ◽  
Author(s):  
Karl R. Kopecky ◽  
Michael C. Hall
Keyword(s):  
Nitro Group ◽  
Considerable Increase ◽  
Phenyl Group ◽  
Diels Alder ◽  
Benzyl Radicals ◽  
Products Of Reaction ◽  
Cis And Trans

Addition of 2,2-diphenyl-1-picrylhydrazyl DPPH to styrene at 75 °C results in little change in the amounts of cis- and trans-1,2-diphenylcyclobutane and 1,2,3,4-tetrahydro-1-phenylnaphthalene, in a slightly smaller amount of 1-phenylnaphthalene, and in a considerable increase in the amount of 1,2-dihydro-1-phenylnaphthalene that are formed. Formation of the styrene trimer 1,2,3,4-tetrahydro-1-phenyl-4-(1-phenylethyl)naphthalene is eliminated completely. Products derived from DPPH are l-(4-nitro-phenyl)-1-phenyl-2-picrylhydrazine 9 and 1-[2,6-dinitro-4-(1,2,3,4-tetrahydro-4-phenyl-1-naphthyl)phenyl]-2,2-diphenylhydrazine, 10. DPPH intercepts the thermally formed Diels–Alder dimer of styrene as soon as it is formed to give the 1,2,3,4-tetrahydro-4-phenyl-1-naphthyl radical.Thermolysis of bis(1,2,3,4-tetrahydro-4-phenyl-1-naphthyl)diazene in the presence of DPPH yields 20% of 10, 10,% of l-[2,6-dinitro-4-(1,2,3,4-tetrahydro-4-phenyl-1-naphthyl)phenyl]-2-(4-nitrophenyl)-2-phenylhydrazine and 9 while thermolysis of 1,2-bis(1-phenylethyl)diazene in the presence of DPPH yields 9 and 44% of 1-[2,6-dinitro-4-(1-phenylethyl)phenyl]-2,2-diphenyl-hydrazine showing that substituted benzyl radicals efficiently displace the 4-nitro group of DPPH. The nitro group is transferred to an unsubstituted phenyl group of DPPH.

Photochemistry of 2,4-Cyclooctadienone I. In Benzene and Toluene

1973 ◽  
Vol 51 (13) ◽  
pp. 2207-2214 ◽  
Author(s):  
Gordon L. Lange ◽  
Eli Neidert
Keyword(s):  
Singlet State ◽  
Alder Reaction ◽  
Diels Alder ◽  
Reactive Intermediate ◽  
Diels Alder Reaction ◽  
Trans Isomerization ◽  
Dimerization Reaction ◽  
Cis And Trans

Irradiation of 2,4-cyclooctadienone (1) in benzene or toluene is shown to give in >80% yield two head-to-head dimers. The ring fusions are shown to occur at the α,β-positions of the dienone with trans-cis and trans-anti-trans stereochemistry. Both dimers may be epimerized to the same product with cis-anti-cis ring fusions. Evidence is presented to show that the singlet state is responsible for the cis-trans isomerization of 1 to the highly reactive intermediate trans, cis-2,4-cyclooctadienone. This intermediate can dimerize in a thermal 2 + 2 cycloaddition or can be generated at −78° and then trapped by 1,3-dienes in a Diels–Alder reaction. A mechanism for the dimerization reaction is discussed.

scholarly journals TiCl3 as a New Catalyst for the Imino Diels-Alder Reaction

2006 ◽  
Vol 1 (9) ◽  
pp. 1934578X0600100
Author(s):  
Narayan V. Mayekar ◽  
Sandip K. Nayak ◽  
Subrata Chattopadhyay
Keyword(s):  
Ambient Temperature ◽  
Alder Reaction ◽  
Diels Alder ◽  
Trans Isomers ◽  
Effective Catalyst ◽  
Diels Alder Reaction ◽  
Cis And Trans Isomers ◽  
Reaction Proceeds ◽  
Cis And Trans

Titanium(III) chloride was found to be an effective catalyst for the imino Diels-Alder reaction between an imine (generated in situ) and an activated alkene in acetonitrile at ambient temperature. The reaction proceeds smoothly to afford the corresponding adduct as a mixture of chromatographically separable cis- and trans isomers in moderate to good yields.

E,E- and E,Z-α-phenyl-α′-acetoxyorthoquinodimethane: steric and electronic control of cycloaddition reactions

1986 ◽  
Vol 64 (4) ◽  
pp. 793-798 ◽  
Author(s):  
James L. Charlton ◽  
Mian M. Alauddin ◽  
Glenn H. Penner
Keyword(s):  
Maleic Anhydride ◽  
Electronic Properties ◽  
Dimethyl Fumarate ◽  
Diels Alder ◽  
Addition Reactions ◽  
Cycloaddition Reactions ◽  
Electronic Control ◽  
Dimethyl Maleate ◽  
Cis And Trans ◽  
Abinitio Calculations

E,E- and E,Z-α-phenyl-α′-acetoxyorthoquinodimethanes have been prepared from the corresponding cis- and trans-1-acetoxy-3-phenyl-1,3-dihydrobenzo[c]thiophene-2,2-dioxides. The regio- and diastereoselectivity of the addition reactions with dimethyl fumarate, dimethyl maleate, maleic anhydride, and methyl crotonate have been determined. Abinitio calculations have been carried out on orthoquinodimethane and its α-phenyl and α-oxy derivatives. A correlation has been made between the steric and electronic properties of the orthoquinodimethanes and the regio- and diastereoselectivity of their Diels–Alder reactions.

Diels–Alder reactions. Part I. The dienophilic properties of cis- and trans-β-formylcrotonic acid and their derivatives

1973 ◽  
pp. 581-583 ◽  
Author(s):  
Barend V. Burger ◽  
Eberhard du Plessis ◽  
Christoph F. Garbers ◽  
Johannes P. van der Merwe
Keyword(s):  
Diels Alder ◽  
Cis And Trans

New synthesis of tetraazachlorins and tetraazabacteriochlorins by Diels–Alder reaction of tetraazaporphine

2000 ◽  
Vol 04 (05) ◽  
pp. 525-531 ◽  
Author(s):  
ELENA A. MAKAROVA ◽  
GALINA V. KOROLYOVA ◽  
OLEG L. TOK ◽  
EVGENY A. LUKYANETS
Keyword(s):  
Electronic Absorption Spectra ◽  
Analysis Data ◽  
Alder Reaction ◽  
Diels Alder ◽  
Elemental Analysis Data ◽  
Tert Butyl ◽  
H Nmr ◽  
Diels Alder Reaction ◽  
Cis And Trans Isomers ◽  
Cis And Trans

The use of the Diels–Alder reaction of unsubstituted tetraazaporphine as dienophile with some dienes of the anthracene series for the synthesis of novel substituted tetraazachlorins, tetraazabacteriochlorins and tetraazaisobacteriochlorins is reported. The condensation of tetraazaporphine with anthracene, 9,10-dimethyl- or 2,6-di(tert-butyl)anthracene in boiling chlorobenzene gives novel dibenzobarreleno-substituted tetraazachlorins 3–5 in yields of up to 71%. When AlCl3 was used as catalyst in the reaction of tetraazaporphine with 2,6-di(tert-butyl) anthracene, the corresponding cis- and trans-dibenzobarreleno-substituted tetraazabacteriochlorins 6a and 6b were obtained. The reaction of tetraazaporphine with the more active diene 2,3-benzanthracene at 130°C gives mainly benzonaphtho[2,3-b]barreleno-substituted tetraazachlorin 7, while the same reaction conducted at 220°C led to a mixture of cis- and trans isomers of tetraazabacteriochlorins 8a and 8b and tetraazaisobacteriochlorins 9a and 9b. The products were characterized using elemental analysis data and mass, 1H NMR and visible spectra. The effect of hydrogenation of one or two double bonds of the tetraazaporphine macrocycle on the electronic absorption spectra is discussed.

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