Malonic acid dibromide

Cyclopropane-1,1-dicarboxylic acid. This compound can be obtained in high yield by double alkylation of diethyl malonate with 1,2-dibromoethane under phase-transfer conditions. Malonic acid cannot be alkylated in this way. 1-Cyanocyclopropanecarboxylic acid can be prepared by reaction of the dibromide with ethyl cyanoacetate (86% yield), ... 

Trimethylene dibromide (1 mol) condenses with ethyl malonate (1 mol) in the presence of sodium ethoxide (2 mols) to form ethyl cydobutane-1 1-dksrboxylate (I). Upon hydrolysis of the latter with alcoholic potassium hydroxide, followed by acidification cyciobutane-1 1-dicarboxylic acid (II) is obtained. 

Tethered diacid 18 was as easily prepared as 8 was (Scheme 6).10 Knoevenagel adduct 20 was deprotonated with NaH and then alkylated with dibromide 9 to give 21 in 59% yield. Alkylation of diethyl malonate with 21 gave 22 in 85% yield, and ozonolysis of 22 and acidic alcoholysis delivered 18 in 88% yield. 

Cyclopropane carboxylic acid (1) Cyclopropane bromide + KCN - cyclopropane cyanide followed by hydrolysis (2) Ethylene dibromide + diethyl malonate - cyclopropane dicarboxylic acid followed by saponification and monodecarboxylation via heating... 

These re sear ches, which are due to iiichael, show that in all probability the reactions between iiiany 0(, -dibromides and sodium malonic ester should be interpreted as follows the dibromide first loses hydro-bromic acid under the influence of the alkaline reagent (sodium alcoholate,as the reaction is usually carried out in the presence of dlcohol)>an oi-brom unsatuxated compound is thus formed which reacts with the L.alonlc ester in the manner outline above for... 

Alkylation of malonic ester by one-half equivalent of an a,-polymethylene bromide gives an a,a,o), o)-tetracarboxylic ester which is hydrolyzed and decarboxylated to an a, fxi-dicarboxylic acid having four more carbon atoms than the dibromide. Good descriptions include those for 1,12-... 

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