Diversity-oriented regioselective domino Michael/Aldol reaction of 3-ylideneoxindoles: A direct access to indanol-fused 3-oxindoles

A diversity-oriented molecular hybridization strategy has been utilized for the synthesis of 2,3-disubstituted 1-indanol-fused 3-oxindoles through a regioselective domino Michael/Aldol reaction of 3-ylideneoxindoles 1 with malononitrile or cyanacetate ethyle 2. Products bearing consecutive stereocenters consist of an oxindole moiety and an indanol core, were smoothly obtained in high yields (up to 92% yield) with good diastereoselectivity (up to 20:1). This protocol also represents the first construction of indanol-fused 3-oxindole scaffolds, thus leading to new knowledge in the fields of both molecular complexity and diversity-oriented synthesis (DOS) and the lead compound discovery. It is also worth mentioning that the reaction was completely regioselective and the competitive regioisomeric products 4 or 5 were not obtained in any case.