Dienolate‐Mediated, Regioselective C2‐Polarity Reversal of Chromone‐Based Reactants and Their Application in Nucleophilic Strategies

Abstract

Inspired by the chemistry and biology of chromone, a method for the construction of spirooxindole-based tetrahydrocyclopenta[b]chromanones is reported with good regio-and diastereoselectivity (all cases > 20:1 dr) and moderate yields (up to 67%). This method leads to the construction of four contiguous stereogenic tertiary centers and one spiro quaternary center via a one-step γ-regioselective cascade [3 + 2] cycloaddition of an oxindole-chromone synthon with 3-methyl-4-nitro-5-alkenyl-isoxazole.

Regioselective synthesis of enantiopure 1,2- and 1,3-dispirooxindoles along with a DFT study

“…Chiral spiro and dispirooxindoles belong to a class of special spiro-heterocyclic compounds, whose synthesis is an important goal due to their biological activity and molecular intricacy. 1 In this family, dispirooxindoles coupled with important heterocycles such as indolizidine, pyrrolizidine, and pyrrolidine are privileged heterocyclic compounds. They are important and abundant in natural alkaloids 2 and pharmaceutical molecules, with a wide range of biological activities including antitumor, antimicrobial, anti-HIV, antimalarial, antiviral, antipyretic, anticancer, and acetylcholinesterase (AChE) inhibitory properties (Fig.…”