Synthesis of Enantiopure 3-Quinuclidinone Analogues with Three Stereogenic Centers: <i>(1S,2R,4S)-</i> and <i>(1S,2S,4S)</i>-2-(Hydroxymethyl)-1-azabicyclo[2.2.2]octan-5-one and Stereocontrol of Nucleophilic Addition to the Carbonyl Group
作者:Jens Frackenpohl、H. M. R. Hoffmann
DOI:10.1021/jo9919815
日期:2000.6.1
The pseudoenantiomeric title compounds have been prepared from quincorine (QCI) and quincoridine (QCD), respectively, in enantiopure form following an efficient six-step pathway. Nucleophilic attack at the carbonyl group proceeds preferentially from the supposedly more hindered endo pi-face, giving quinuclidinols with natural configuration at C5 (up to 97%). pi-Face selectivity is highest in the QCD series with bulky O-protecting groups, involving an unprecedented 1,7-stereoinduction.