Highly diastereoselective catalytic Meerwein-Ponndorf-Verley reductions.
[reaction: see text] Very practical synthesis of ephedrine analogues in high yields and enantiopurity was realized by a highly diastereoselective Meerwein-Ponndorf-Verley (MPV) reduction of protected alpha-amino aromatic ketones using catalytic aluminum isopropoxide. The high anti selectivity resulted from the chelation of the nitrogen anion to the aluminum. In contrast, high syn selectivity was obtained with alpha-alkoxy ketones and other compounds via Felkin-Ahn control.
Yin
Jingjun
J
Department of Process Research, Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065, USA. jingjun_yin@merck.com
Huffman
Mark A
MA
Conrad
Karen M
KM
Armstrong
Joseph D
JD
D000588:Amines; D004809:Ephedrine / Q000031:analogs & derivatives* / Q000138:chemical synthesis*; D006841:Hydrocarbons, Aromatic; D007202:Indicators and Reagents; D007659:Ketones; D008958:Models, Molecular; D008968:Molecular Conformation; D012997:Solvents; D013237:Stereoisomerism
D000588:Amines; D006841:Hydrocarbons, Aromatic; D007202:Indicators and Reagents; D007659:Ketones; D012997:Solvents; D004809:Ephedrine