Herstellung von 1, 3‐Diketonen und von Nitro‐diketonen durch (1:1)‐Acylierungen von Lithiumenolaten mit Acylchloriden

Preparation of 1,3‐Diketones and of Nitro‐diketones by (1:1)‐Acylation of Lithium Enolates with Acyl Chlorides Slow addition of precooled solutions of lithium enolates in THF (Fig. 1) to solutions of equimolar amounts of acyl chlorides in the same solvent at temperatures between − 80 and − 100° furnishes 1, 3‐diketones in acceptable to good yields (Tables 1−3). Even 3‐nitropropionyl and 4‐nitrobutyryl chloride can be employed for the (1:1)‐acylation of enolates to give the synthetically useful 5‐ and 6‐nitro‐1, 3‐diketones 13 and 25, respectively. The scope and the limitations of this method of preparing 1, 3‐diketones are given and are compared with alternative methods.