Design, synthesis and application of a new type of bifunctional Le-Phos in highly enantioselective γ-addition reactions of N-centered nucleophiles to allenoates
作者:Haile Qiu、Xiaofeng Chen、Junliang Zhang
DOI:10.1039/c9sc04073k
日期:——
A novel class of bifunctional cyclic phosphine catalysts (Le-Phos) is reported, which showed good performances in enantioselective γ-addition reactions of N-centered nucleophiles and allenoates under mild conditions.
contiguous three stereocenters has been a long-standing challenging task in organic synthesis. Herein we present a phoshine-catalyzed highly regio-, diastereo- and enantioselective [3+2] cycloaddition of γ-substitutedallenoates with β-perfluoroalkyl enones, delivering a wide range of densely functionalized perfluoroalkylated cyclopentenes with three contiguous chiral stereocenters.
Phosphine-Catalyzed Formation of Carbon−Sulfur Bonds: Catalytic Asymmetric Synthesis of γ-Thioesters
作者:Jianwei Sun、Gregory C. Fu
DOI:10.1021/ja101251d
日期:2010.4.7
only add to the gamma position of allenoates, overcoming their propensity to add to the beta position in the absence of a catalyst, but do so with very good enantioselectivity. Sulfur nucleophiles are now added to the three families of nucleophiles (carbon, nitrogen, and oxygen) that had earlier been shown to participate in catalyzed gamma additions. The phosphine catalyst of choice, TangPhos, had
PPh3-catalyzed β-selective addition of α-fluoro β-dicarbonyl compounds to allenoates
作者:Yong-Liang Liu、Xiao-Ping Wang、Jie Wei、Ya Li
DOI:10.1016/j.tet.2021.132577
日期:2022.1
A highly selective phosphine-catalyzed β-addition of α-fluoro β-dicarbonylcompounds to allenoates has been developed. Both α-fluoro β-diketones and α-fluoro β-keto esters prove to be competent fluorocarbon nucleophiles, giving a series of the β-addition products bearing a fluorinated quaternary carbon center in good to excellent yields and with excellent regioselectivities. A plausible reaction pathway