The asymmetric hydrogenation of 1,1,4,4,7-pentamethyl-2-methylen-1,2,3,4-tetrahydro-naphthalene, a viable catalytic approach to the synthesis of non-racemic Fixolide®
文摘
Asymmetric hydrogenation of 1,1,4,4,7-pentamethyl-2-methylen-1,2,3,4-tetrahydro-naphthalene 2 or 1,1,2,4,4,7-hexamethyl-1,4-dihydronaphthalene 3 leads to 1,1,2,4,4,7-hexamethyl-1,2,3,4-tetrahydro-naphthalene 4 an immediate precursor of the fragrance Fixolide®. Promising results (with 33 % ee) have been obtained starting from olefin 2 using a cationic Iridium catalyst in combination with a chiral phosphino-oxazoline ligand.