Abstract Compounds of the formula I and II M1, M2 and M3 independently of one another are no bond, a direct bond, CO, O, S, SO, S02 or NR14 provided that at least one of M1, M2 or M3 is a direct bond, CO, O, S, SO, S02 or NR14 M4 is a direct bond, CRM3R"4, CS, O, S, SO, or S02 Y is S or NR18 R1 for example is hydrogen, C3-C8cycloalkyl, phenyl or naphthalene, both of which are optionally substituted R2 for example is C1-C20a!kyl R"2 has one of the meanings given for R2 R3 and R4 are for example hydrogen, halogen, C1-C20alkyl R3l R4l R"3 and R"4 independently of one another have one of the meanings given for R3 and R4 and R5 is for example hydrogen, halogen, C1-C20 alkyl provided that in the compounds of the formula I at least two oxide ester groups are present exhibit an unexpectedly good performance in photo polymerization reactions.
