for the following products
(6R,7R)-7-Amino-3-ethenyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid | (6R,7R)-7-Amino-8-oxo-3-vinyl-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid | 7-Amino-3-vinyl-3-cephem-4-carboxylic acid and 7-AVCA