Preparation and Diels-Alder Reactions of 1,1-Dicarbonylalkanes

Article abstract of DOI:10.1021/jo00142a028

1,1-Dicarbonyl- (ester, ketone, lactone) substituted alkenes are prepared from the corresponding saturated 1-phenylsulfinyl derivatives.These are formed from precursor sulfides, which can be efficiently prepared either by oxidation of β-hydroxy-α-phenylsulfenylcarbonyl compounds or direct acylation of α-phenylsulfenyl enolate anions with acid chlorides.Some of the title compounds can be isolated and then reacted while others are generated and reacted in situ in a Diels-Alder fashion with cyclopentadiene.Endo-exo selectivities are discussed.