90054-58-3

bp 68–70°C/5 mmHg.

1,2-Diethoxy-1,2-bis(trimethylsilyloxy)- ethylene is used in synthetic equivalent of the acyl anion C(O)CO2Et; useful in ZnCl2-mediated nucleophilic additions to aldehydes and ketones, Michael additions to enones,and substitution reactions of SN1-active alkyl halides1 and carboxylic acid chlorides.

can be prepared in one step from diethyl oxalate using the R¨1hlmann version of the acyloin condensation (eq 1).Although a yield of 64% of isolated product was reported,this could not be reproduced in a careful series of experiments.Rather, yields of 21¨C25% are consistently obtained (0.1¨C1.0 molar scale).The product consists of a (Z/E) isomeric mixture which is of no consequence for synthetic applications.

Somewhat air and moisture sensitive and should therefore be handled and stored under an atmosphere of an inert gas such as N2 and in nonprotic solvents. Use in a fume hood.