A magnesium enamide derived from N-2-(N′,N′-dimethylamino)ethylimine reacts with primary and secondary alkyl chlorides and fluorides to give an α-alkylated ketone in good to excellent yields upon hydrolysis of the imine moiety. Reactions of the highly nucleophilic magnesium enamide derived from an unsymmetrical ketone take place regioselectively. In addition, the C–C bond formation is stereospecific:
Electronic and conformational effects on .pi.-facial stereoselectivity in nucleophilic additions to carbonyl compounds
作者:Yun Dong Wu、K. N. Houk
DOI:10.1021/ja00237a051
日期:1987.2
Influnce des interactions de torsion dans la reduction des cetones par les hydrures interpretation generale du deroulement sterique de la reduction des cetones acycliques et de l'addition des organomagnesiens sur les aldehydes acycliques
作者:M. Cherest、N. Prudent
DOI:10.1016/s0040-4020(01)83128-8
日期:1980.1
Reduction of ketones L-CHMe-CO-R [L=Ph and Cy(Cy = cyclohexyl) and R=Me, Et, iPr and tBu] affords pairs of diastereoisomeric alcohols L-CHMe-CHOH-R. The predominant diastereoisomer is always that predicted by Cram's rule, and the stereoselectivity of the reaction generally increases as R is made more bulky. Thus, with LiAlH4 in ether at 35°, the diastereoisomer ratios are respectively 2.8:1, 3.2:1