反应详情

5,6-Dihydro-2H-pyran-2-one is treated with vinyllithium in the presence of a cuprous salt to obtain 4-ethenyl-tetrahydro-2H-pyran-2-one which is reacted with 3-bromopyridine under conditions of a Heck condensation [J. Org. Chem. 43, 2952 (1978), e.g. in the presence of Pd(OAc)2 and tri-o-tolylphosphine] to obtain 4-[2-(3-pyridyl)-ethenyl]tetrahydro-2H-pyran-2-one. The lactone is reduced to the corresponding lactol, e.g. with diisobutyl aluminium hydride, which is condensed under Wittig conditions with e.g. methyl(triphenylphosphoranylidene)-acetate to obtain methyl 7-hydroxy-5-[2-(3-pyridyl)-ethenyl]-hept-2-enoate. The two double bonds are then saturated using e.g. hydrogen in the presence of palladium on charcoal catalyst to obtain methyl 7-hydroxy-5-[2-(3-pyridyl)-ethyl]-heptanoate. The alcohol is converted to a reactive intermediate, e.g. the mesylate derivative, treated with e.g. sodium cyanide to obtain the nitrile which is then reduced to the methyl ester of the amine of formula XII wherein Het represents 3-pyridyl, A and M represent 1,3-propylene and B represents 1,2-ethylene.