Catalytic Asymmetric Construction of Spirocycles Containing Pyrrolidine Motifs and Spiro Quaternary Stereogenic Centers via 1,3‐Dipolar Cycloaddition of Azomethine Ylides with 2‐Alkylidene‐Cycloketones

• DOI: 10.1002/adsc.201100104
• Publication Date: 2011-07-07T16:39:33Z
• Authors: Tang‐Lin Liu; Zhao‐Lin He; Qing‐Hua Li; Hai‐Yan Tao; Chun‐Jiang Wang
• Keywords: Pyrrolidine; Stereocenter

Abstract The first catalytic asymmetric 1,3‐dipolar cycloaddition of azomethine ylides with various sterically hindered α,α,β‐trisubstituted 2‐alkylidene‐cycloketones has been developed successfully silver acetate/TF‐BiphamPhos complex for the construction spiro heterocyclic compounds containing pyrrolidine motifs and a quaternary stereogenic carbon center. highly efficient system exhibited high reactivity, excellent diastereoselectivity, good enantioselectivity broad substrate scope under mild conditions. Subsequent transformations led to expedient preparation synthetically useful spiro[pyrrolidine‐tetrahydropyranone] spiro[pyrrolidine‐isochroman‐1‐one] without loss diastereo‐ enantiomeric excesses.