Cyclopentene-3,5-diones monoacetal

Feringa s group has demonstrated that cyclopentene-3,5-dione monoacetals as 2-47 can also be successfully applied as substrates in an asymmetric three-component domino Michael/aldol reaction with dialkyl zinc reagents 2-48 and aromatic aldehydes 2-49 [17]. In the presence of 2 mol% of the in-sitw-generated enantiomeri-cally pure catalyst Cu(OTf)2/phosphoramidite 2-54, the cyclopentanone derivatives 2-51 were formed nearly exclusively in good yields and with high ee-values (Scheme 2.11). 

Photochemical addition of tetramethylethylene to 4,4-dimethylcyclopentenone or the monoacetal of cyclopentene-3,5-dione yields both the oxetans and the cyclobutane products. The ratio of the products is solvent dependent. The factors affecting oxetan and cyclobutane formation in the photochemical addition of olefins to enones have been investigated. ... 

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