Synthesis of cyclopentadiene derivatives

A process for preparing a cyclopentadiene derivative having formula (I)

• wherein
• T1is selected from the group consisting of oxygen (O), sulphur (S) and NR, wherein R is selected from the group consisting of linear or branched saturated or unsaturated C1-C20-alkyl, C3-C20-cycloalkyl, C6-C20-aryl, C7-C20-atkylaryl, and C7-C20-arylalky radical, optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements;
• R1, R2, equal to or different from each other are hydrogen or a linear or branched saturated or unsaturated C1-C20-alkyl, C3-C20-cycloalkyl, C6-C20-aryl, C7-C20-alkylaryl or C7-C20-arylalkyl radical, optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements;
• or they can form a C4-C7 ring optionally containing O, S, N, P or Si atoms that can bear substituents;
• W is a moiety of formula (a) or (b)
• wherein
• T2, T3, T4, T5 equal to or different from each other are selected from the group consisting of nitrogen (N) and CR3 wherein R3 is hydrogen or a linear or branched saturated or unsaturated C1-C20-alkyl, C3-C20-cycloalkyl, C6-C20-aryl, C7-C20-atkylaryl or C7-C20-arylalkyl radical, optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements;
• or two adjacent R3 groups can form a C4-C7 ring optionally containing O, S, N, P or Si atoms, wherein said ring can bear substituents;
• T6 has the same meaning as T1;
• T7 and T8 equal to or different from each other are selected from N and CR3 wherein R3 is hydrogen or a linear or branched saturated or unsaturated C1-C20-alkyl, C3-C20-cycloalkyl, C6-C20-aryl, C7-C20-alkylaryl or C7-C20-arylalkyl radical, optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements;
• optionally two adjacent R3 groups can form a C4-C7 ring optionally containing O, S, N, P or Si atoms, said ring can bear substituents;
• with the proviso that when T6 is different from NR, T7 and T8 are both CR3;
• said process comprising the following steps:
• a) reacting a compound of formula (II)
• with a compound of formula (III)
• in the presence of a coupling system, wherein X is selected from the group consisting of chlorine, iodine, and bromine;
• thereby forming a compound of formula (IV)
• b) contacting the compound of formula (IV) with a carbonylating system;
• thereby forming a compound of formula (IVa)
• and;
• c) treating the compound of formula (IVa) with a reducing agent.