Organocatalytic Asymmetric Michael Addition/Annulation Cascade toward the β-Nitro Chromones.

An efficient and practical one-pot protocol has been developed for the enantioselective synthesis of chiral β-nitro chromones under mild conditions. This method combines organocatalyzed Michael addition of 1,3-diketones to nitroalkenes with subsequent acid-promoted annulation. The reaction tolerates a wide range of substrates, delivering the target products in up to 90% yield with up to 97% ee (32 examples). Moreover, the process is scalable, and the products can be readily transformed into functionalized derivatives, offering a versatile route to highly substituted heterocyclic frameworks.