Enols as Feasible Acid Components in the Ugi Condensation
摘要:
Heterocyclic enols are used for the first time as acid components in an Ugi-type multicomponent condensation. For that purpose, we have chosen enols containing a Michael acceptor, in order to facilitate an irreversible rearrangement of the primary Ugi adduct. The new four-component process leads readily and efficiently to heterocyclic enamines containing at least six elements of diversity.
Enol-Ugi Reaction of Hydroxycoumarins: Straightforward Synthesis of Amino Acid Derived Coumarin Enamines
作者:Ana Neo、Carlos Marcos、Teresa Castellano
DOI:10.1055/s-0034-1380436
日期:——
Hydroxycoumarins containing electron-withdrawing groups have been successfully used as acidic components in Ugi-type multicomponent condensations with imines and isocyanides. The reaction takes place smoothly at room temperature, with no need of catalysis, affording 3- and 4-coumarin enamines in a highly convergent manner. Key to this transformation is the conjugate addition--elimination rearrangement on the primary adduct, irreversibly leading to the final product.