Cyclopropane-1,1-dicarboxylates

The procedure (with ethylene dibromide replacing trimethyleiie dibromide) described for cycZobutanecarboxylic acid (previous Section) does not give satisfactory results when applied to the cyclopropane analogue the yield of the cyclopropane-1 1 dicarboxylic acid is considerably lower and, furthermore, the decarboxylation of the latter gives a considerable proportion (about 30 per cent.) of butyrolactone ... 

Some straightforward, efficient cyclopentanellation procedures were developed recently. Addition of a malonic ester anion to a cyclopropane-1,1-dicarboxylic ester followed by a Dieckmann condensation (S. Danishefsky, 1974) or addition of iJ-ketoester anions to a (l-phenylthiocyclopropyl)phosphonium cation followed by intramolecular Wittig reaction (J.P, Marino. 1975) produced cyclopentanones. Another procedure starts with a (2 + 21-cycloaddition of dichloroketene to alkenes followed by regioselective ring expansion with diazomethane. The resulting 2,2-dichlorocyclopentanones can be converted to a large variety of cyclopentane derivatives (A.E. Greene. 1979 J.-P. Deprds, 1980). 

It is noteworthy that in the synthesis of 117, the smaller Ugi macrocycle 118 was also formed. The lack of sterically demanding isopropyl groups in comparison to 113 allows the formation of this somewhat strained macrocycle. Because of this intriguing result, the diacid component in this reaction was varied to cyclopropane-1,1-dicarboxylic acid (Scheme 24) and tereph-thalic acid (Scheme 25). 

Cyclopropane-1,1-dicarboxylic acid [598-10-7] M 130.1, m 140 . Recrystd from CHCI3. 

HOMOCONJUGATE ADDITION OF NUCLEOPHILES TO CYCLOPROPANE-1,1-DICARBOXYLATE DERIVATIVES PREPARATION OF 2-OXO-1-PHENYL-3-PYRROLIDINECARBOXYLIC ACID... 

A. Preparation of cyclopropane 1,1 -dicarboxylic acid (1). To a 1-L solution of aqueous 50% sodium hydroxide (Note 1), mechanically stirred in a 2-L, three-necked flask, was added, at 25°C,... 

Previously cyclopropane-1,1-dicarboxylic acid had been prepared2-4 by hydrolysis of the corresponding diester. The preparation of 1,1-dicarboalkoxycyclopropanes by a conventional double alkylation of diethyl malonate with 1,2-dibromoethane was severely complicated by the recovery of unreacted diethylmalonate. This required a rather difficult distillation to separate starting material and product. In fact, many commercially offered lots of cyclopropane diester contain extensive amounts of diethyl malonate. Furthermore, preparation of the diacid required a separate and relatively slow saponification of the diester.5... 

---