An array of deconjugated linear 3,5-dienones with substantial substitutions have been successfully used in β,ε-regioselective Diels–Alder cycloadditions with 3-olefinic oxindole-based dienophiles via trienamine catalysis of cinchona-based primary amines, efficiently producing spirocyclic oxindole architectures with dense and diverse substitutions in high stereoselectivity (up to 99% ee, >19 : 1 d.r.).