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

作者：Coskun Necdet; Cetin Meliha; Gronert Scott^*; Ma Jingxiang; Erden Ihsan

来源：Tetrahedron, 2015, 71(18): 2636-2642.

DOI：10.1016/j.tet.2015.03.042

• Fulvene
• Michael addition
• Chalcone
• 1,2-Dihydropentalene
• Iminium ions

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.

• 出版日期2015-5-6