Cyclopentadienyl, indenyl or fluorenyl substituted phosphine compounds and their use in catalytic reactions

A phosphine compound represented by the general formula (4):

• or its corresponding phosphonium salt represented by the general formula (4a):
• wherein
• R′ and R″ are each independently selected from alkyl, cycloalkyl and 2-furyl radicals, or R′ and R″ are joined together to form with the phosphorous atom a carbon-phosphorous monocycle comprising at least 3 carbon atoms or a carbon-phosphorous bicycle;
• the alkyl radicals, cycloalkyl radicals, and carbon-phosphorous monocycle being unsubstituted or substituted by at least one radical selected from the group consisting of alkyl, cycloalkyl, aryl, alkoxy, and aryloxy radicals;
• R is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-octadecyl, benzyl, and phenyl radicals that are unsubstituted;
• R11, R12, R13, R14, R15, R16, R17, and R18 are each independently selected from the group consisting of H;
• aliphatic, heteroaliphatic, aromatic, alicyclic, heterocyclic radicals, heteroatom-containing radicals comprising an aromatic, alicyclic, or heterocyclic radical and an additional heteroatom linking the aromatic, alicyclic, or heterocyclic radical atom with the carbon atom of the fluorenyl group, all the foregoing radicals being unsubstituted or substituted by further carbon and/or heteroatoms;
• halogens;
• and heteroatom-containing groups;
• or adjacent groups selected from R11, R12, R13, R14, R15, R16, R17, and R18 together form a divalent radical thereby forming a fused ring system;
• and Y− represents an anion.