Access to Wieland–Miescher Diketone-Derived Building Blocks by Stereoselective Construction of the C‑9 Quaternary Carbon Center Using the Mukaiyama Aldol Reaction

The Mukaiyama aldol reaction has
been used to efficiently install
a lateral chain at the C-9 position of the Wieland–Miescher
ketone derivative 3 within two steps, representing a
shortcut compared to that of the classical sequences. The treatment
of the silylated enol ether 8 with a wide range of acetals
in the presence of tin tetrachloride led to a the diastereoselective
construction of the C-9 quaternary center of 33 new building blocks
derived from the Wieland–Miescher ketone derivative 3.