Catalysis of mukaiyama aldol reactions by a tricyclic aluminum alkoxide Lewis acid.
The Mukayiama aldol reaction of aldehydes is efficiently accomplished with a low concentration of the dimeric alumatrane catalyst 2 at mild or subambient temperatures. Our protocol tolerates a wide variety of electron-rich, neutral, and deficient aryl, alkyl, and heterocyclic aldehydes. A wide variety of enol silyl ethers are also tolerated. An intermediate that was isolated provides mechanistic information regarding the role of dimeric 2 in the Mukaiyama aldol reaction. Experimental evidence is presented for the stronger Lewis acidity of 5 compared with F3B.
Raders
Steven M
SM
Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
Verkade
John G
JG