title: Pyrrolidine catalyzed reactions of cyclopentadiene with α,β-unsaturated carbonyl compounds: 1,2- versus 1,4-additions.
abstract: A systematic study of the reactions of cyclopentadiene with α,β-unsaturated carbonyl compounds in the presence of catalytic pyrrolidine-H2O revealed that the reactions can either proceed with a Michael attack at the β-carbon of enone, or 1,2-addition to the carbonyl, leadingeither to 4-cyclopentadienyl-2-butanones or 6-vinylfulvenes. The former can be isolated and/or converted to the corresponding 1,2-dihydropentalenes with base (or in one-pot at longer reaction times). Substitution pattern on the enones on the competing pathways have been studied and consistent mechanisms are proposed.
authors.affiliation: On leave from Uludag University, Department of Chemistry, 16059 Bursa-Turkey.
authors.forename: Necdet
authors.initials: N
authors.lastname: Coskun
authors.affiliation: On leave from Uludag University, Department of Chemistry, 16059 Bursa-Turkey.
authors.forename: Meliha
authors.initials: M
authors.lastname: Çetin
authors.affiliation: Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, Richmond, Virginia, 2384, Oliver Hall 3041.
authors.forename: Scott
authors.initials: S
authors.lastname: Gronert
authors.affiliation: San Francisco State University, Department of Chemistry and Biochemistry, 1600 Holloway Avenue, San Francisco, CA 94132.
authors.forename: Jingxiang
authors.initials: J
authors.lastname: Ma
authors.affiliation: San Francisco State University, Department of Chemistry and Biochemistry, 1600 Holloway Avenue, San Francisco, CA 94132.
authors.forename: Ihsan
authors.initials: I
authors.lastname: Erden
keywords: 1,2-Dihydropentalene; Chalcone; Fulvene; Iminium ions; Michael addition