Pyrrolidine catalyzed reactions of cyclopentadiene with alpha,beta-unsaturated carbonyl compounds.: 1,2-versus 1,4-additions

Coskun N., Cetin M., Gronert S., Ma J., Erden I.

TETRAHEDRON, cilt.71, sa.18, ss.2636-2642, 2015 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 71 Sayı: 18
  • Basım Tarihi: 2015
  • Doi Numarası: 10.1016/j.tet.2015.03.042
  • Dergi Adı: TETRAHEDRON
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.2636-2642
  • Anahtar Kelimeler: Fulvene, Michael addition, Chalcone, 1,2-Dihydropentalene, Iminium ions, EFFICIENT METHOD, EXCEPTIONALLY SIMPLE, CONDENSATION, FULVENES, 1,2-DIHYDROPENTALENES
  • Bursa Uludağ Üniversitesi Adresli: Evet

Özet

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.