Bicatalytic Multistep Reactions En Route to the One-Pot Total Synthesis of Complex Molecules: Easy Access to Chromene and 1,2-Dihydroquinoline Derivatives from Simple Substrates

By combining nanocatalysis with base catalysis, a novel one-pot multistep process was found for the synthesis of substituted heterocycles of biological relevance from simple substrates. The process is based on the initial Au/O2oxidation of allylic alcohols, which is followed by base-catalyzed tandem hetero-Michael/aldolization/crotonization with ortho-hydroxy- or ortho-aminobenzaldehydes. The flexibility of the reaction even allowed the benzaldehyde partner to be prepared in situ in an example of a one-pot/five-step process.