Stereoselective conjugate addition of chiral β-dicarbonyl derivatives to methyl vinyl ketone was promoted by electrolysis, using a catalytic amount of electricity. With respect to the metal-catalyzed methods, the electrochemical, metal-free conditions resulted in enhanced reactivity of the electrogenerated enolates, so that the Michael addition was found to occur under mild conditions and short reaction times, affording products with significant diastereoisomeric excesses. When Oppolzer's sultam was used as the chiral inductor and prolonged reaction times were employed, a reversal in the stereoselectivity was observed, evidencing kinetic control in the electrochemically-induced addition and subsequent thermodynamic equilibration. The electrochemically-based method was also exploited for the elaboration of quaternary stereogenic carbon centers. © 2002 Elsevier Science Ltd. All rights reserved.
Electrochemically-initiated Michael addition of chiral acetoacetic derivatives to methyl vinyl ketone: Stereocontrolled construction of quaternary carbon centers / Laura, Palombi; Feroci, Marta; Monica, Orsini; Inesi, Achille. - In: TETRAHEDRON-ASYMMETRY. - ISSN 0957-4166. - STAMPA. - 13:21(2002), pp. 2311-2316. [10.1016/s0957-4166(02)00636-5]
Electrochemically-initiated Michael addition of chiral acetoacetic derivatives to methyl vinyl ketone: Stereocontrolled construction of quaternary carbon centers
FEROCI, Marta;INESI, ACHILLE
2002
Abstract
Stereoselective conjugate addition of chiral β-dicarbonyl derivatives to methyl vinyl ketone was promoted by electrolysis, using a catalytic amount of electricity. With respect to the metal-catalyzed methods, the electrochemical, metal-free conditions resulted in enhanced reactivity of the electrogenerated enolates, so that the Michael addition was found to occur under mild conditions and short reaction times, affording products with significant diastereoisomeric excesses. When Oppolzer's sultam was used as the chiral inductor and prolonged reaction times were employed, a reversal in the stereoselectivity was observed, evidencing kinetic control in the electrochemically-induced addition and subsequent thermodynamic equilibration. The electrochemically-based method was also exploited for the elaboration of quaternary stereogenic carbon centers. © 2002 Elsevier Science Ltd. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.