Organocatalytic synthesis of spirocyclohexane indane-1,3-diones via a chiral squaramide-catalyzed Michaelfaldol cascade reaction of γ-nitro ketones and 2-arylideneindane-1,3-diones

The paper presents an efficient and stereoselective method for constructing spirocyclohexane indane-1,3-diones. This method is based on a chiral squaramide-catalysed highly diastereo- and enantioselective cascade Michael/aldol reaction between gamma-nitro ketones and 2-arylidene-1,3-indanedione that affords functionalised spirocyclohexane products in high chemical yields with the formation of three stereogenic centres (57-97%; up to >20;1 dr and 86% ee). (C) 2015 Elsevier Ltd. All rights reserved.