The discovery of reaction regime controlled product diversification in a one-pot reaction between diynones and dimethyl-1,3-acetonedicarboxylate (DMAD) to selectively furnish either functionally unique pentasubstituted o-alkynylbenzoates or fully substituted furan-3(2H)-ones is delineated. The potential of these two versatile platforms to enter new utilitarian chemical space has also been explored.

Spiroannulation of oxindole-3-oxy acrylates with ynones involving two overlapping, base differentiated cascades has been observed. Initial exposure of ynones and oxindole 3-oxy acrylates to K 2 CO 3 triggered a tandem Michael−Michael cascade to deliver a pair of spiroannulated diastereomers. Further exposure to LiHMDS led to deep restructuring through a second multistep cascade involving stereoselective recreation of the C3 quaternary center to furnish 3Hspiro[furan-2,3′-indolin]-2′-ones with functional amplification and scrambling. This new scaffold can be directly accessed in a one-flask operation from ynones and oxindole-3-oxy acrylates.