A process for the synthesis of a polycarbonate, the process comprising the step of reacting carbon dioxide with at least one epoxide in the presence of a catalyst of formula: wherein R 1 and R 2 are independently hydrogen, halide, a nitro group, a nitrile group, an imine, an amine, an ether group, a silyl ether group, or an acetylide group or an optionally substituted alkyl, alkenyl, alkynyl, haloalkyl, aryl, heteroaryl, alicyclic or heteroalicyclic group; R 3 is independently selected form optionally substituted alkylene, alkenylene, alkynylene, heteroalkylene, heteroalkenylene, heteroalkynylene, arylene, heteroarylene or cycloalkylene, wherein alkylene, alkenylene, alkynylene, heteroalkylene, heteroalkenylene and heteroalkynylene, may optionally be interrupted by aryl, heteroaryl, alicyclic or heteroalicyclic; R 4 is independently selected from H, or optionally substituted aliphatic, heteroaliphatic, alicyclic, heteroalicyclic, aryl, heteroaryl, alkylheteroaryl or alkylaryl; R 5 is H, or optionally substituted aliphatic, heteroaliphatic, alicyclic, heteroalicyclic, aryl, heteroaryl, alkylheteroaryl or alkylaryl; E 1 is C, E 2 is O, S or NH or E 1 is N and E 2 is O; X is independently selected from OC R x, OSO 2 R x, OSOR x, OSO(R x) 2, OR x, phosphinate, halide, nitrate, hydroxyl, carbonate, amido or optionally substituted aliphatic, heteroaliphatic, alicyclic, heteroalicyclic, aryl or heteroaryl; R x is independently hydrogen, or optionally substituted aliphatic, haloaliphatic, heteroaliphatic, alicyclic, heteroalicyclic, aryl, alkylaryl or heteroaryl; G is absent or independently selected from a neutral or anionic donor ligand which is a Lewis base; M is independently selected from Zn, Cr, Co, Mn, Ti, Mg, Fe, Cr -X, Co -X, Mn -X, Fe -X, Ca, Ge, Al -X, Ti -X, V -X, Ge - 2 or Ti - 2; and a chain transfer agent selected from water or a compound of formula: Z (̵W) n wherein Z is an optionally substituted moiety selected from the group consisting of aliphatic, heteroaliphatic, alicyclic, heteroalicyclic, aryl, heteroaryl, polyolefin, polyester, polyether, polycarbonate or combinations thereof, each W is independently selected from a hydroxyl, amine, thiol or carboxylic acid, and n is an integer which is at least 1 wherein when the chain transfer agent is water, it is present in a molar ratio of at least 1:1 relative to the catalyst of formula. wherein R 1 and R 2 are independently hydrogen, halide, a nitro group, a nitrile group, an imine, an amine, an ether group, a silyl ether group, or an acetylide group or an optionally substituted alkyl, alkenyl, alkynyl, haloalkyl, aryl, heteroaryl, alicyclic or heteroalicyclic group; R 3 is independently selected form optionally substituted alkylene, alkenylene, alkynylene, heteroalkylene, heteroalkenylene, heteroalkynylene, arylene, heteroarylene or cycloalkylene, wherein alkylene, alkenylene, alkynylene, heteroalkylene, heteroalkenylene and heteroalkynylene, may optionally be interrupted by aryl, heteroaryl, alicyclic or heteroalicyclic; R 4 is independently selected from H, or optionally substituted aliphatic, heteroaliphatic, alicyclic, heteroalicyclic, aryl, heteroaryl, alkylheteroaryl or alkylaryl; R 5 is H, or optionally substituted aliphatic, heteroaliphatic, alicyclic, heteroalicyclic, aryl, heteroaryl, alkylheteroaryl or alkylaryl; E 1 is C, E 2 is O, S or NH or E 1 is N and E 2 is O; X is independently selected from OC R x, OSO 2 R x, OSOR x, OSO(R x) 2, OR x, phosphinate, halide, nitrate, hydroxyl, carbonate, amido or optionally substituted aliphatic, heteroaliphatic, alicyclic, heteroalicyclic, aryl or heteroaryl; R x is independently hydrogen, or optionally substituted aliphatic, haloaliphatic, heteroaliphatic, alicyclic, heteroalicyclic, aryl, alkylaryl or heteroaryl; G is absent or independently selected from a neutral or anionic donor ligand which is a Lewis base; M is independently selected from Zn, Cr, Co, Mn, Ti, Mg, Fe, Cr -X, Co -X, Mn -X, Fe -X, Ca, Ge, Al -X, Ti -X, V -X, Ge - 2 or Ti - 2; and a chain transfer agent selected from water or a compound of formula: Z (̵W) n Z is an optionally substituted moiety selected from the group consisting of aliphatic, heteroaliphatic, alicyclic, heteroalicyclic, aryl, heteroaryl, polyolefin, polyester, polyether, polycarbonate or combinations thereof, each W is independently selected from a hydroxyl, amine, thiol or carboxylic acid, and n is an integer which is at least 1 wherein when the chain transfer agent is water, it is present in a molar ratio of at least 1:1 relative to the catalyst of formula.