I realize this doesn't directly answer your question, but you may find it easier to do a 2+2 with ketene and a carbonyl. The product will still be the beta lactone your after.

J. Phys. Chem. A 2006, 110, 207-218.

Perhaps look at the degradation process of glow sticks (the light-emitting step).

Thank you Brennan. However my objective is the sequestration of CO2 by photochemical means.

Thanks again

Raju