Asymmetric Construction of a Multi-Pharmacophore-Containing Dispirotriheterocyclic Scaffold and Identification of a Human Carboxylesterase 1 Inhibitor.

A catalytic asymmetric [3 + 2] cyclization of novel 4-isothiocyanato pyrazolones and isatin-derived ketimines was developed, delivering a wide range of intriguing dispirotriheterocyclic products in high yield with excellent diastereoselectivity and enantioselectivity. A chiral sulfoxide derivative of this dispirocyclic product was identified to be a promising hit of the human carboxylesterase 1 inhibitor, and the significant difference of the activity between two enantiomers emphasized the importance of this asymmetric process.