2-Trimethylsilythiazole (2) and 2,5-bis(tri-methylsilyl) thiazole (6) undergo ipso-substitution of the 2-SiMe3 group with various ketens affording the thiazolyl-trimethylsiloxy-ethylenes (3) and(7), respectively, which are hydrolysed to the 2-acylthiazoles (4), whereas 5-trimethylsilylthiazole (8) undergoes attack at C-2 by dichloroketen giving the Michael-type adduct 2-dichloro-acetyl-5-trimethylsilylthiazole