A method for the control of absolute stereochemistry in
morphine syntheses has been demonstrated by the resolution
and efficient racemization of the advanced morphine precursor , 9-methoxy-3-methyl-5,6-dihydro-3H-benzofuro[3,2-e]isoquinoline-
7(7aH)-one, I. This was accomplished by the facile coversion of optically resolved I to its ring opened
form, 5,6,7,8-tetrahydro-10-methoxy-3-methyl-7-oxo[1]benzoxonino[
6,7-c]pyridinium tosylate, II, (Equation...