Abstract
We recently reported the preparation of the new trioxoylides 1 and their pyrolysis to give symmetrical diacylalkynes.1 Reaction of acyl ylides with oxalyl chloride gkes the tetraoxo diylides 2 as shown. The corresponding reactions starting from the α-oxoacyl ylides have been used to obtain examples of tetraoxo ylides 3 and hexaoxo diylides 4.