A 2.5 M n-BuLi solution in hexane (16.80 mL, 42.00 mmol, n-BuLi:fluorene=1.04:1) was added dropwise at 0° C. under stirring to a solution of 6.70 g of fluorene (40.31 mmol) in 100 ml of Et2O in a 500 mL 3-necked round flask. The resulting orange solution was allowed to warm up to room temperature and stirred for 1 h. A solution of chloro(2,4,7-trimethylindenyl)dimethylsilane (10.05 g, 40.06 mmol) in 20 mL of THF was cooled to 0° C. and slowly added to the lithium salt solution, also previously cooled to 0° C. At the end of the addition an orange-brown suspension was obtained. The latter was allowed to warm up to room temperature and stirred for 1.5 h. Then the reaction mixture was evaporated under reduced pressure to give a brown sticky solid, which was treated at r.t. with 150 mL of toluene and finally filtered to remove LiCl. The filtrate was dried in vacuo to give 16.48 g of a reddish oil, whose 1H NMR showed it to be the target compound contaminated by minor amounts of not identified by-products (crude yield quantitative). The product was used as such in the next step without further purification.
