1,1-Cyclobutanedicarboxylate, reaction

Some examples of alkylation reactions involving relatively acidic carbon acids are shown in Scheme 1.3. Entries 1 to 4 are typical examples using sodium ethoxide as the base. Entry 5 is similar, but employs sodium hydride as the base. The synthesis of diethyl cyclobutanedicarboxylate in Entry 6 illustrates ring formation by intramolecular alkylation reactions. Additional examples of intramolecular alkylation are considered in Section 1.2.5. Note also the stereoselectivity in Entry 7, where the existing branched substituent leads to a trans orientation of the methyl group. 

The steam distillation separates ethyl malonate and ethyl 1,1-cyclobutanedicarboxylate from ethyl pentane-1,1,5,5-tetra-carboxylate, formed in a side reaction between malonic ester (2... 

Sulfonium, cyclopropyldiphenyl tetrafluoroborate, 54, 28 Sulfonium salts, acetylenic, furans from, 53, 3 Sulfonium ylides, 54, 32 Sulfur, reaction with organo-lithium compounds, 50, 105 Sulfuryl chloride, with 1,1-cyclobutanedicarboxylic acid to give 3-chloro-l,1-cyclobutanedicarboxylic acid, 51, 73... 

Dicarboxylic acids give very poor yields of the cyclopropane under Kolbe reaction conditions. ITie cyclobutanedicarboxylic acid 25 affords a bicyclobutane [132], 2,2-DiraethyIglutaric acid gives low yields of a hydrocarbon, which is not... 

Methylene groups can be dialkylated if sufficient base and alkylating agent are used. Dialkylation can be an undesirable side reaction if the monoalkyl derivative is the desired product. Use of dihaloalkanes as the alkylating reagent leads to ring formation, as illustrated by the diethyl cyclobutanedicarboxylate synthesis (entry 7) shown in Scheme... 

These reactions can be used to understand many of the structure-function relationships among the approved drugs and those that have undergone clinical testing. For example, carboplatin retains the cis -diammineplatinum(II) center, but the chlorides have been replaced by the cyclobutanedicarboxylate ligand. The similar array of... 

In the very early years of imprinting, carboxylic acid ester moieties were used as binding groups. The aim was the preparation of microreactors for regio- and stereoselective reactions. For this, the cavity was first imprinted with a possible product of the reaction and a precursor was then embedded into the cavity. The idea was to favour the formation of the product used as template by running the reaction within the imprinted cavity. The first experiments were carried out by the research groups of Shea [90,91] and Neckers [92], who performed cycloadditions that led to cyclo-propanedicarboxylic and cyclobutanedicarboxylic acids, respectively. The latter... 

---