Carbon-carbon bond-forming reactions on mesoporous silica catalyst

摘要

Mesoporous silica material was employed as solid acid catalyst for Friedel-Crafts acylation and Mukaiyama-aldol reaction, and revealed to be very effective. On 90 mg/mmol of MCM-41, acid anhydrides were rapidly activated and coupled with anisole at 180 deg C to afford corresponding ketones in good to high yields (up to 89 percent). In Mukaiyama-aldol reactions, acetals were selectively activated and gave corresponding aldol-type products in high yields (up to 97 percent) even in the co-existence of aldehydes. We also concluded that the present catalytic activity does not result from impurities in the wall such as aluminum ions by comparing its catalytic activity with those of similar siliceous materials such as dealuminated MCM-41, aluminated MCM-41, non-ordered silica gel, and commercially available silica gel.