In the presence of a mesoporous aluminosilicate Al-MCM-41, aldolreaction of various silyl enol ethers with both aromatic and aliphatic aldehydes proceeded under mild reaction conditions to afford the corresponding O-silylated aldol adducts in high yields. The solid acid catalyst was easily recovered and reusable three times.
In the silylLewis acid-promoted Mukaiyamaaldolreaction, the steric and electronic properties of the silyl group on the silylLewisacid influence the reaction mechanism and product distribution. When super silyl triflates such as (TMS)3SiOTf and (TES)3SiOTf are used as Lewisacids, the silyl group of the silyl enol ether chemoselectively transfers to the product. The mechanistic details have been