A new protocol for the synthesis of α′,β′-unsaturated 1,3-diketones
作者:Renato Dalpozzo、Antonio De Nino、Emma Iantorno、Giuseppe Bartoli、Marcella Bosco、Letizia Sambri
DOI:10.1016/s0040-4020(96)01148-9
日期:1997.2
Dianions of α′-(trimethylsilyl)enaminones can be used as Peterson reagents in the reaction with aldehydes and ketones, to obtain α′,β′-unsaturated enaminones or 1,3-diketones with regio and stereocontrol of the new double bond.
An Efficient, Scaleable Procedure for the Conversion of Esters to Isoxazoles
作者:W. H. Bunnelle、P. R. Singam、B. A. Narayanan、C. W. Bradshaw、J. S. Liou
DOI:10.1055/s-1997-1211
日期:1997.4
A concise, regiocontrolled route to isoxazoles, based on the condensation of an ester with a metallated imine, has been developed. The intermediate vinylogous amides react smoothly with hydroxylamine to provide, after dehydration, substituted isoxazoles. The method has been used for the multi-kilo scale preparation of ABT-418, a novel cholinergic channel activator.
One-pot formation of aza-enolates from secondary amines and condensation to esters and alkyl bromides
作者:Alice Chevalley、Jean-Pierre Férézou
DOI:10.1016/j.tet.2012.04.105
日期:2012.7
Starting from commercial secondary amines, a one-pot procedure allows a direct access to enaminones through a one-pot deprotonation/oxidation/in situ re-deprotonation/acylation sequence without intermediate isolation of the intermediate Schiff base or its corresponding enamine tautomer. An alternative one-pot sequence involving a similar oxidation step followed by one or two alkylation steps yields