β-Silyl-Assisted Tandem Diels-Alder/Nazarov Reaction of 1-Aryl-3-(trimethylsilyl) Ynones.

A one-pot tandem Diels-Alder/Nazarov reaction of 1-aryl-3-(trimethylsilyl) ynones has been achieved to generate carbo- and heterocyclic fused ring systems in good to excellent yields. The β-silyl effect is instrumental in accessing this otherwise challenging cascade annulation reaction. The tandem reaction proceeds in the presence of BCl3 to generate three new carbon-carbon bonds, a quaternary carbon, and two stereogenic centers with excellent diastereocontrol. A variety of substituted arenes, and even heteroaromatics, are tolerated to provide tricyclic products that are of interest as advanced intermediates toward biologically relevant compounds.