Dimethylketene methyl trimethylsilyl acetal

Clear colorless liquid

bp 35 °C/15 mmHg; d 0.858 g cm3.

1-Methoxy-2-methyl-1-(trimethylsiloxy)propene is used in the synthesis of chiral β-lactams by reacting with (S)-alkylidene(1-arylethyl)amines in the presence of titanium tetrachloride. It acts as a catalyst or initiator in the group-transfer polymerization. It is also used as a versatile reagent in conjugate addition4 and aldol reactions.

1-Methoxy-2-methyl-1-(trimethylsilyloxy) propene is widely used as functional equivalent of enolate of methyl isobutyrate; ester enolate surrogate in electrophilic reactions including alkylation, aldol reaction, Michael reaction, initiator for group transfer polymerization of acrylates, nitroarylation, oxidation, dimerization, and cycloadditions.

The title compound is a prototypical ketene silyl acetal (KSA) that can been prepared by either of the two most commonly employed methods: (a) deprotonation of the |á-hydrogen of an ester followed by silylation (1),16 and (b) metal-catalyzed hydrosilylation of |á,|-unsaturated esters(2).

Add Et2O, wash with cold H2O, dry (Na2SO4), filter, evaporate Et2O, and distil the oily residue in a vacuum. [Ainsworth et al. J Organometal Chem 46 59 1972.]