A new family of spirooxindole amides were synthesized by a sequence of hydrozirconation, acylation, and intramolecular cyclization reactions. Three of the four possible diastereomers can be obtained as the major isomers through this process. The spirooxindole structure has many points for diversification, and a 37-membered library was synthesized through this approach by collaborators. A comparison with known compound collections showed that this new spirooxindole library possessed good chemical diversity.
Cyanohydrin alkyl ethers, the key intermediate in the above multi-component hydrozironation reaction, were effectively synthesized through a Brønsted acid-mediated hydrocyanation of vinyl ethers. The enantiomerically enriched product can be obtained by asymmetric hydrocyanation of vinyl ethers catalyzed by a chiral Brønsted acid, and the catalyst
can be regenerated by PhOH. As far as we know, this research represents the first example of chiral Brønsted acid mediated intermolecular addition of silylated nucleophiles with vinyl ethers. The ion pair interaction between the conjugate base of the chiral Brønsted acid and the
oxocarbenium ion was revealed by computational modeling, which explained the origin of the enantioselectivity and the substrate scope of this reaction
