Nickel-Catalyzed Asymmetric Negishi Cross-Couplings of Secondary Allylic Chlorides with Alkylzincs
摘要:
Complementing previous advances in allylation chemistry, an effective nickel/Pybox catalyst for regioselective asymmetric Negishi cross-couplings of racemic secondary allylic chlorides with readily available organozinc halides has been developed. The method has been applied in two key steps of a formal total synthesis of fluvirucinine A(1).
alkyl-substituted acyclic allylic systems with a stereocenter in the allylicposition is reported. The asymmetric induction and the site selectivity are controlled in an enantio- and regioconvergent nickel-catalyzed C(sp3)−C(sp3) cross-coupling of regioisomeric mixtures of racemic α-/γ-silylated allylic halides and primary alkylzinc reagents. The silylgroup steers the allylic displacement towards the