Synthesis of 2-bromo-9H-fluoren-9-one (3096-56-8)

The preparation of 2-Bromo-9-fluorenone is performed in the following way:
Alkylation of the lithium salt of 2-(3,4-dimethoxyphenyl)isobutyronitrile (I) with 1,3-dibromopropane (II) gave the bromo nitrile (III). Conversion of bromide (III) into the desired primary amine (VI) was achieved through a Gabriel synthesis by condensation with potassium phthalimide (IV), followed by hydrazinolysis of the resultant N-substituted phthalimide (V). A two-step procedure was finally employed for the reductive alkylation of amine (VI), consisting of condensation between amine (VI) and the bromo fluorenone (VII) in the presence of titanium isopropoxide and then reduction of the intermediate (VIII) with NaBH3CN.