Diastereoselective access to [4,4]-carbospirocycles: governance of thermodynamic enolates with an organocatalyst in vinylogous cascade annulation.
Vinod BhajammanavarSumitava MallikVenkata Surya Kumar ChoutipalliVenkatesan SubramanianMahiuddin BaidyaPublished in: Chemical communications (Cambridge, England) (2022)
A vinylogy concept driven annulation strategy is developed to access [4,4]-carbospirocycles from alkylidene malononitriles and cyclopentene-1,3-diones. The reaction is catalyzed by an inexpensive organocatalyst and products with three stereocenters were obtained as a single diastereomer in high yields. The spiro-selectivity originates from the reaction of the thermodynamic enolate intermediate which is fundamentally intriguing.