Patent ID: 8258328

Claim:
A method for preparing compounds of general formula (I): wherein Z is a linear alkyl radical or a group R 4 of the formula: wherein n is an integer from 2 to 8, and R 1 and R 2 are identical or different and independently of each other selected from benzyl, linear, branched or cyclic C 1 -C 8 alkyl, C 1 -C 8 alkenyl or C 1 -C 8 alkynyl; or R 1 and R 2 taken together with the nitrogen atom to which they are attached form a saturated or unsaturated, aromatic or nonaromatic 5- to 6-membered heterocycle optionally containing from 1 to 3 additional heteroatoms and optionally fused with another ring; A is a keto functional group or a group CH—X, wherein X is a halogen atom; R 3 is hydrogen or a hydroxyl protecting group; comprising: a) subjecting a mixture of the compounds of formulae (IIIa) and (IIIb): wherein A is as defined above and ═K is a protected keto functional group selected from ketal, thioketal or a mixed ketal, to an alkylation reaction with an organocuprate derivative derived from an organometallic compound of formula R 5 MgHal or R 5 Li, Hal being a halogen atom and generated catalytically or stoichiometrically, wherein R 5 is: wherein Z is as defined above, the bonding taking place on the phenyl, wherein said mixture of the compounds of formulas (IIIa) and (IIIb) comprises greater than or equal to 30% by weight of the compound of formula (IIIb); and reacting with a suitable deprotecting agent so as to obtain the compounds of formulae (Va), (Vb) and (Vc): and b) treating the compounds of formulae (Va), (Vb) and (Vc) with a aromatization agent so as to obtain a mixture of the compounds of formulae (VI) and (I): which continue to undergo aromatization so as to obtain the compound of formula (I) wherein R 3 is as defined above.