Pyrrolidine catalyzed reactions of cyclopentadiene with alpha,beta-unsaturated carbonyl compounds.: 1,2-versus 1,4-additions
TETRAHEDRON, vol.71, no.18, pp.2636-2642, 2015 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 71 Issue: 18
- Publication Date: 2015
- Doi Number: 10.1016/j.tet.2015.03.042
- Journal Name: TETRAHEDRON
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Page Numbers: pp.2636-2642
- Keywords: Fulvene, Michael addition, Chalcone, 1,2-Dihydropentalene, Iminium ions, EFFICIENT METHOD, EXCEPTIONALLY SIMPLE, CONDENSATION, FULVENES, 1,2-DIHYDROPENTALENES
- Bursa Uludag University Affiliated: Yes
Abstract
A systematic study of the reactions of cydopentadiene with alpha,beta-unsaturated carbonyl compounds in the presence of catalytic pyrrolidine-H2O revealed that the reactions can either proceed with a Michael attack at the beta-carbon of enone, or 1,2-addition to the carbonyl, leading either 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. (C) 2015 Elsevier Ltd. All rights reserved.