Diastereoselective access to [4,4]-carbospirocycles: governance of thermodynamic enolates with an organocatalyst in vinylogous cascade annulation

Chem Commun (Camb). 2022 Feb 10;58(13):2188-2191. doi: 10.1039/d1cc06544k.

Abstract

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.