A squaramide‐catalyzed asymmetric Michael/cyclization tandem reaction between 3‐hydroxychromenones and isatylidenemalononitriles was developed. Using this strategy, a wide scope of spiro[indoline‐3,4′‐pyrano[3,2‐b]chromene] derivatives, which combined chromone, pyran, indolone in one molecule, could be obtained in moderate to excellent yields (up to 94 %) with moderate enantioselectivities (up to 95 % ee). In addition, the scaled‐up experiment also confirmed the synthetic practicality of this synthetic strategy.
No takes yet. Share an insight, caveat, or question.
Geng et al. (2024) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: