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Photochemical generation of vinylketenes by electrocyclic opening of cyclobutenones

โœ Scribed by Alfred Hassner; Simha Naidorf

Book ID
104221226
Publisher
Elsevier Science
Year
1986
Tongue
French
Weight
227 KB
Volume
27
Category
Article
ISSN
0040-4039

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โœฆ Synopsis

4,4-Dichloro-'2-cyclobutenones 1_, available by cycloaddition of acetylenes to dichloroketene, can be photolyzed in the presence of olefins or dienes to produce regiospecifically Z-vinylcyclobutanones &&. The photochemical reaction succeeds even in some cases where thermolysis fails and was shown to proceed by electrocyclic ring opening to a vinylketene. Stereochemically the results of photolysis of j_ differ from thermolysis with identical olefinic substrates. Ketenes have long been known as useful reactive intermediates, and the reaction of dichloroketene with olefins has found many synthetic and mechanistic applications.2 Recently

๐Ÿ“œ SIMILAR VOLUMES

Vinylketenes from Cyclobutenones by Elec
Vinylketenes from Cyclobutenones by Electrocyclic Ring Opening
โœ Dr. Herbert Mayr ๐Ÿ“‚ Article ๐Ÿ“… 1975 ๐Ÿ› John Wiley and Sons ๐ŸŒ English โš– 223 KB

## 2,4,4-Trimethyl-2-cyclobutenone ( 9 ) 3-Ethoxy-2,4,4-trimethylcyclobutanone (19.0g, 0.1 2mol) in ether (290ml) was mixed to a paste with neutral AI,O, (230g); after 24h the mixture was poured onto a column of dry A1,0, (100g) and eluted with ether (800ml). The solvent was removed by fractional