This review summarizes the very recent advances in organocatalytic asymmetric cycloaddition reactions involving ortho-quinone methides (o-QMs), a family of versatile species that have proven useful in a broad range of reactions to afford diverse chiral molecules. In the past years, different kinds of organocatalysts have been developed into a privileged class of catalytic systems in asymmetric synthesis.A number of remarkable achievements have been made by many groups around the world. Due to length limitation, this review only summarizes those works published from January 2016 to December 2020. Meanwhile, catalytic systems which combine metal catalysts and organocatalysts will not be discussed in this review.
An asymmetric synthesis of epoxyoxindoles from isatins has been developed by employing chiral sulfur ylides generated in situ from camphor-derived sulfonium salts. This reaction allows an efficient access to enantioenriched spiro-epoxyoxindoles under mild reaction conditions, featuring high yields and excellent enantio- and diastereoselectivities.
A catalytic asymmetric allylic alkylation reaction of 3‐aryloxindoles was accomplished via a dual catalysis merging palladium catalysis and asymmetric H‐bonding catalysis for the first time. Using this approach, allylated oxindoles bearing chiral all‐carbon quaternary centers were produced in high yields with good enantioselectivities (up to 92 % yield and 96:4 er).magnified image
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