Ketone enolates as nucleophiles in palladium-catalysed allylic alkylation

Abstract

Lithium enolates from pentan-3-one, cyclohexanone, acetophenone, and mesityl oxide react with some representative (acyclic and cyclic) allylic acetates in a palladium-catalysed alkylation in good yields and under mild conditions; the substitution is shown to proceed with retention of configuration.

Stereochemical Control in Palladium‐catalyzed Allylic Etherification

“…Since the optimal concentration of dba is about 2 equiv per palladium, one may add either dba to Pd(PPh,), or the appropriate amount of phosphine ligand to a solution of Pd2(dba),. 19 Indeed, when l b and 2 were reacted in benzene at 40 "C in the presence of 4.5 mol % Pd,(dba), and mphenylphosphine (1.6 equiv per Pd), thereaction was completed within 10 h, yielding product 3b with 92% stereospecificity. This latter approach is desirable due to the ready availability and air-stability of Pd,(dba),, as well as flexibility in choosing the phosphine ligand.…”

Tsuji–Trost Allylic Alkylation with Ketone Enolates

“…It seems that, owing to early disappointing results, organic chemists avoided attempts to carry out palladium‐catalyzed allylation reactions with preformed “hard” enolates. The few approaches did not have much success4a or remained unnoticed 4b,c. Stereoselective variants of this transformation, in particular, had not been developed until the beginning of this decade 5…”

Tsuji‐Trost‐Allylierung mit Ketonenolaten

“…Es scheint, dass man aufgrund früher, enttäuschender Resultate vor Umsetzungen von Allylpalladium‐Komplexen mit “harten” Enolaten zurückschreckte. Vereinzelte Versuche waren entweder wenig erfolgreich4a oder blieben unbeachtet 4b,c. Insbesondere stereoselektive Varianten dieser Umsetzung wurden erst mit Beginn dieses Jahrzehnts entwickelt 5…”