A highly chemoselective Mukaiyama aldol reaction of saturated aldehyde over unsaturated aldehyde with enol tris(2,6-diphenylbenzyl)silyl ether

An exceedingly high chemoselective Mukaiyama aldol reaction of saturated aldehydes in the presence of unsaturated aldehydes (benzaldehyde and α,β-enals) has been realized for the first time by using the structurally unique enol tris(2,6-diphenylbenzyl)silyl ether under the influence of BF3·OEt2 as a Lewis acid. Among unsaturated aldehydes, benzaldehyde is found to be more reactive than α,β-enals. The structural uniqueness of the enol tris(2,6-diphenylbenzyl)silyl ether can be visualized by X-ray crystallography as well as 1H and 13C NMR spectroscopy.