Supported ligands having a high local density of coordinating atoms

9) A method of synthesizing a compound of formula (1), comprising the steps of:

• a) introducing a functional group GF, comprising a vinyl group —CH═CH2, and a spacer E, which is —CH2—, comprising reacting 6,6-dimethylfulvene with a methyl group the organomagnesium compound CH2═CH—CH2—MgCl, to produce 1-[2-(2-methyl)pent-4-enyl]cyclopentadiene,
• b) reacting the product obtained in step a) in a lithiation reaction with n-BuLi, to produce 1-[2-[2-methyl]pent-4-enyl]cyclopentadienyllithium,
• c) reacting the product obtained in step b) with ClP(Ph)2 in two successive phosphinations reactions, between which a step of lithiation with n-BuLi is carried out,
• d) treating the compound obtained in step c) with n-BuLi, to produce 1,2-bis(diphenylphosphino)-4-[2-(2-methyl)pent-4-enyl]cyclopentadienyllithium, and
• e) synthesizing the compound of formula (1) by reacting FeCl2 with the compound obtained in step d).

10) A method of synthesizing the compound of formula (2), comprising the steps of:

• a) reacting an organomagnesium compound of the formula below:
• wherein X is Br or I with CH3COCl, to produce 4-(1,3-dioxan-2-yl)butan-2-one of formula A below:
• b) reacting the compound of formula A obtained in step a), with pyrrolidine and cyclopentadienyllithium (CpLi), to give the produce 2-[3-(cyclopenta-2,4-dienylidene)butyl]-1,3-dioxane of formula B below:
• c) reacting the compound of formula B in a lithiation reaction with methyllithium (MeLi), to produce a compound of formula C below:
• d) preforming two successive phosphinations of the compound of formula C with ClP(Ph)2, with intermediate passage to the lithium salt corresponding to the monophosphination by action of n-BuLi, followed by a treatment with n-BuLi, to produce a compound of formula D below:
• e) reacting the compound of formula D with an iron salt to produce a compound of formula (2) below: