One-Pot Enol Silane Formation-Mukaiyama Aldol Reactions: Crossed Aldehyde-Aldehyde Coupling, Thioester Substrates, and Reactions in Ester Solvents
Trimethylsilyl trifluoromethanesulfonate (TMSOTf) and a trialkylamine base promote both in situ enol silane/silyl ketene acetal formation and Mukaiyama aldol addition reactions between a variety of reaction partners in a single reaction flask. Isolation of the required enol silane or silyl ketene acetal is not necessary. For example, crossed aldol reactions between α-disubstituted aldehydes and non-enolizable aldehydes yield b- hydroxy aldehydes in good yield. In a related reaction, the common laboratory solvent ethyl acetate functions as both an enolate precursor and a green reaction solvent. When thioesters are employed as enolate precursors, high yields for additions to non-enolizable aldehydes are routinely observed.
Copyright © 2019, Tetrahedron Letters.
C. Wade Downey, Grant J. Dixon, Jared A. Ingersoll, Claire N. Fuller, Kenneth W. MacCormac, Anna Takashima, Rohina Sediqui. One-pot enol silane formation-Mukaiyama aldol reactions: crossed aldehyde-aldehyde coupling, thioester substrates, and reactions in ester solvents. Tetrahedron Letters 2019, 60, Article 151192.