Water-Compatible Iminium Activation: Organocatalytic Michael Reactions of Carbon-Centered Nucleophiles with Enals
作者:Claudio Palomo、Aitor Landa、Antonia Mielgo、Mikel Oiarbide、Ángel Puente、Silvia Vera
DOI:10.1002/anie.200703261
日期:2007.11.12
Highly Stereoselective Asymmetric Construction of an Acyclic Carbon Skeleton Having Two Adjacent Alkyl Substituents by Michael Addition of Optically Active Allenyltitaniums to Alkylidenemalonates
作者:Yongcheng Song、Sentaro Okamoto、Fumie Sato
DOI:10.1021/ol016652p
日期:2001.11.1
[GRAPHICS]Enantio-enriched allenyltitaniums prepared in situ by the reaction of optically active secondary propargyl phosphates with a divalent titanium reagent Ti(O-i-Pr)(4)/2i-PrMgCl react readily with alkylidenemalonates with excellent regio- and diastereoselectivities to afford the Michael addition products with a high optical purity, thus opening up a new asymmetric method for construction of an acyclic carbon skeleton bearing two adjacent alkyl substituents.