24 r 17 r 18 r 19 and r 20 can be bonded to each other to form a ring or rings catalyst g1 described in u s pat no 6 852 865 that is cp 2 ti thf 2 co co 4 where cp means cyclopentadienyl has been found not to work at all for epoxide carbonylation carried out at co pressures of 100 psig and below and is excepted from the catalysts herein the catalyst a herein can be made by reaction of m jr q x u2032 where m jr q is defined as for catalyst a with qm u2032 co y u2014 y u2032 where qm u2032 co y is defined as for catalyst a and x u2032 is any leaving group and y u2032 is a moiety that will form a salt with x u2032 we turn now to the catalyst e it is readily made as described in supporting information for kramer j w et al org lett 8 17 3709 3712 jul 18 2006 the whole of which is incorporated herein by reference we turn now to the reaction conditions besides starting material co pressure and catalyst the mole ratio of component i charged to catalyst charged can range for example from 1 1 to 10 000 1 for example from 25 1 to 150 1 for subset a the mole ratio used in the examples was 100 1 for subset b the mole ratio used in the examples was 50 1 where the co pressure is greater than 1 atm e g when it is 100 psig the pressure and the volume of the reactor define the amount of co where the co pressure is one atmosphere the amount of co is provided by the headspace in the.