Practical synthesis of (-)-morphine

The hydrophenanthrenone approach to the synthesis of morphinane alkaloids s uch as (-)-dihydrocodeinone (16) is described, Optical activity is achieved by chiral resolution of the hydrophenanthrenone derivative 6 on cellulose triacetate. Key steps of the thirteen-step synthesis are the conjugate addi tion of vinyl cuprate to 6, which generates the crucial benzylic quaternary center and the demethylative cycloetherification step that transforms brom oketone 8 into morphinane 9. Chirality 11: 475-482, 1999. (C) 1999 Wiley-Li ss, Inc.