Asymmetric α-regioselective annulation of MBH carbonates with 4-arylmethylisoxazol-5-ones has been developed to afford spirocyclic oxindole derivatives containing three contiguous stereogenic centers and vicinal all-carbon quaternary chiral centers. This reaction exhibits a broad substrate scope and excellent functional group tolerance. Excellent yields with high diastereoand enantioselectivities were obtained in this efficient organocatalytic reaction.
A base promoted formal [4+1] cycloaddition of ortho‐ and para‐quinone methides with 3‐chlorooxindoles is reported to afford various functionalized 3,2′‐tetrahydrofuryl spirooxindoles in high yields under mild conditions. An unexpected reversal in diastereoselectivity was observed from these two types of reactions. Computational studies have provided insight into the origin of diastereoselection, and different configurations of 1,4‐addition and 1,6‐addition at the oxindole carbanionic center are found to give rise to different diastereomers. The anti‐tumor activity of these structurally unique spirooxindole derivatives is reported.
A highly efficient base-mediated diastereoselective [4+1] cycloaddition of ortho-tosylaminophenyl-substituted p-QMs with 3-chlorooxindoles has been developed to afford 3,2’-pyrrolidinyl spirooxindoles in high yields with high diastereoselectivity through domino 1,6-addition/cyclization sequence. This...
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