Patent ID: 7381718

Claim:
A process for the preparation of a compound of the formula selected from the group consisting of wherein either R 1 and R 2 , are individually selected from the group consisting of benzyl, alkyl, alkenyl, and alkynyl of up to 8 carbon atoms and cycloalkyl of 3 to 8 carbon atoms or R 1 and R 2 form together with the nitrogen which carries them an aromatic or non-aromatic, saturated or unsaturated heterocycle of 5 to 6 ring members, optionally containing from 1 to 3 additional heteroatoms, and optionally connected to another ring, R 3 is hydrogen or a protective group of the hydroxy function, n is an integer from 2 to 8 comprising reacting a compound of the formula K is a protected ketone function with a silylation agent in the presence of a base, to obtain a silylated enol of the formula wherein Ra, Rb and Rc, are individually alkyl of 1 to 4 carbon atoms or phenyl, reacting the said compound of formula III with an organocuprate derivative, derived from the organometallics R 5 MgHal or R 5 Li, Hal being halogen and generated in a catalytic or stoichiometic fashion, in which R 5 is n, R 1 and R 2 being as defined above, to obtain a compound of the formula which is isolated or non-isolated: and then reacted with a deprotection agent to obtain a compound of the formula: and reacting the latter with an aromatization agent to obtain the expected compound of formula (I) and optionally subsequently deprotecting to obtain a compound of formula (I) with R 3 is hydrogen.