Novel catalysts for reaction between an isocyanate and an alcohol

A process for preparing a compound A having at least one urethane functional group, the process comprising a stage 1) which comprises reacting a compound B, having at least one isocyanate functional group, with a compound D, having at least one hydroxyl functional group, in the presence of a catalytically effective amount of at least one catalyst C, wherein the catalyst C is a metal complex or salt of following formula (1):

• [Zn(L1)l1(L2)l2(Y)x] (1)
• in which:
• l1≧1 and l2=0 or 1;
• with l1+l2=2, x=0, 1 or 2,
• the symbol L2 represents an anionic ligand which is different from L1,
• the symbol Y represents a neutral ligand, and
• the symbol L1 is a β-diketonato anion derived from a β-diketone of formula R1COCHR2COR3 (2) and said β-diketone is selected from the group consisting of β-diketones:
• 2,4-hexanedione;
• 2,4-heptanedione;
• 3,5-heptanedione;
• 3-ethyl-2,4-pentanedione;
• 5-methyl-2,4-hexanedione;
• 2,4-octanedione;
• 3,5-octanedione;
• 5,5-dimethyl-2,4-hexanedione;
• 6-methyl-2,4-heptanedione;
• 2,2-dimethyl-3,5-nonanedione;
• 2,6-dimethyl-3,5-heptanedione;
• 2-acetylcyclohexanone (Cy-acac);
• 2,2,6,6-tetramethyl-3,5-heptanedione (t-Bu-acac);
• 2,2,7-trimethyl-3,5-octanedione;
• 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (F-acac);
• benzoylacetone;
• dibenzoylmethane;
• 3-methyl-2,4-pentanedione;
• 3-acetylpentane-2-one;
• 3-acetyl-2-hexanone;
• 3-acetyl-2-heptanone;
• 3-acetyl-5-methyl-2-hexanone;
• stearoylbenzoylmethane;
• octanoylbenzoylmethane;
• 4-(t-butyl)-4′-methoxydibenzoylmethane;
• 4,4′-dimethoxydibenzoylmethane;
• 4,4′-di(tert-butyl)di-benzoylmethane and 2,4-undecanedione.

A compound selected from formulae (7) to (9):

• (7):
• [Zn(UDD)2], with (UDD)=a 2,4-undecanedionato anion or an enolate anion of 2,4-undecanedione,
• (8):
• [Zn(TMOD)2(N,N′-dimethylethylenediamine)], with (TMOD)=a 2,2,7-trimethyl-3,5-octanedionato anion or an enolate anion of 2,2,7-trimethyl-3,5-octanedione, and
• (9):
• [Zn(TMOD)2(N-propylethylenediamine)], with (TMOD)=a 2,2,7-trimethyl-3,5-octanedionato anion or an enolate anion of 2,2,7-trimethyl-3,5-octanedione.