Process for preparing cyclic carbonates

A process for preparing a cyclic carbonate of formula Ia or Ib or a mixture thereof

• wherein R1 is hydrogen or an organic radical having from 1 to 40 carbon atoms,
• the process comprising:
• a) reacting a propargylic alcohol of formula II
• wherein R1 is defined as in formula Ia or Ib,
• with carbon dioxide in the presence of at least one transition metal catalyst TMC1, which comprises:
• a transition metal selected from metals of groups 10, 11 and 12 of the periodic table of the elements;
• and at least one bulky ligand selected from the group of ligands consisting of a compound of formula III and a compound of formula IV
• wherein D is P, As or Sb,
• R2, R3, R4 and R5 are each independently an organic radical having from 1 to 40 carbon atoms, and
• Z is a divalent bridging group selected from —CR7═CR8—, —CR7═N—, —CR7R9—CR8R10— and —CR7R9—CR8R10—CR11R12—, wherein R7, R8, R9, R10, R11 and R12 are each independently hydrogen or an organic radical having from 1 to 40 carbon atoms or two adjacent radicals R7 and R8 and/or R10 and R11 together with the atoms connecting them form a monocyclic or polycyclic, substituted or un- substituted, aliphatic or aromatic ring system which has from 4 to 40 carbon atoms and optionally comprises at least one heteroatom selected from the group of elements consisting of Si, Ge, N, P, O and S.