Stereocontrolled syntheses of epimeric 3-aryl-6-phenyl-1-oxa-7-azaspiro[4.5]decane NK-1 receptor antagonist precursors

[GRAPHICS] Complementary stereoselective syntheses of individual C3 epimers of the NK- 1 receptor antagonist precursor 1 have been developed. Both diastereomers w ere derived from the common intermediate 3; introduction of the 3S stereoce nter in 1a was achieved through hydrogenation of an arylated dihydrofuran, whereas the corresponding stereogenic center in 1b was installed using a st ereo- and regioselective alkene hydroarylation.