1.2- Cyclopropanedicarboxylic esters

Treatment of bistrimethylsilyl enol ethers of glutaric esters with TiC leads to the stereoselective formation of rruns-1,2-cyclopropanedicarboxylic esters (equation 35). ... 

Dilithium enolates of glutaric esters undergo oxidative coupling to produce 1,2-cyclopropanedicarboxylic esters Cupric halides have been found to be the most satisfactory reagents for this coupling among various oxidants examined (equation 40) . ... 

Oxidative 1,3-coupling of dicarboxylic esters via treatment with lithium diisopropylamide in the presence of chlorotrimethylsilane gave bis-silylenol ethers, which on reaction with tita-nium(IV) chloride produced cyclopropanedicarboxylic esters 11 in moderate yield.It is assumed that initial conversion to an enoxy radical takes place via a titanium enolate, followed by a diradical 1,3-coupling. 

TT-Allylplladium zwitterions are generated from 2-vinyl-l,l-cyclopropanedicarboxylic esters on treatment with an analogue of (dba)3Pd2. These species can be trapped by aldehydes. 

FIGURE 16. VCD and absorption spectra in the CH stretching region of (+)-dimethyl trans-1, 2-cyclopropanedicarboxylate with d3 methyl groups (a) rfg-ester (lUde), (b) (/g-ester tn CCU. Reprinted with permission from Heintz and Keiderling, J. Am. Chem. Soc., 103, 2395,... 

Most of the nucleophilic openings of cyclopropanes have involved two geminally placed activating groups, usually esters. Thus, cyclopropanedicarboxylates (18) have undergone... 

The most widely explored method is the formation of tri- and tetrasubstituted cyclopropanes by reaction of vinylsulfonium salts with methylene compounds activated by ester, ketone, nitrile, or sulfone substituents. A series of examples is collected in Table 25. A variant of this method, where cyclopropanedicarboxylates cis-1 were actually obtained by intramolecular cyclization of the sulfonium salt Cj building block is also shown.Alkylthiocyclopropane derivatives 8 were obtained by the reaction of a ketene dithioacetal monosulfonium salt with carbanions derived from doubly activated methylene compounds. ... 

This profound transformation occurs on treatment of aryl-substituted cyclopropanes with powerful oxidizing agents, such as ozone and ruthenium(Vlll) oxide to give the corresponding cyclopropanecarboxylic acids. The results obtained using ozone appear to be sensitive to the reaction conditions, therefore, ruthenium(VIII) oxide has become the reagent of choice for such transformations. An exception is the formation of the monomethyl ester of tran5-l,2-cyclopropanedicarboxylic acid in quantitative yield by ozone treatment of methyl t/ nA-2-phenylcyclopropanecarboxylate. ... 

The spiro-lactone structure of isopropylidene 1,1-cyclopropanedicarboxylates 7 increases the electrophilic character of the cyclopropane ring. When isopropylidene 1,1-cyclopropanedi-carboxylate was heated in aqueous acetone, water was added across the proximal C-C bond of the ring followed by the formation of y-lactone 8 and hydrolysis of the second ester function. The corresponding bicyclo[4.1.0]heptanedicarboxylate reacted in the same fashion to afford the tra 5-lactone as a result of an inversion of configuration upon the nucleophilic attack by water. °... 

The cooperative effect ( 1.6) of two esters can improve selectivity Alkylation of dimenthyl succinate 1.21 (n = 2) by BrCH Cl in the presence of base leads, after hydrolysis, to nonracemic trans- 1,2-cyclopropanedicarboxylic acid with an excellent enantiomeric excess [12] (Figure 5.17). However, on the way to estrone, Quinkert and coworkers had to use (l ,2ft5S)-phenmenthol dimalonale 5.26 to synthetize methyl 2-vinylcydopropane-l, l-dicaibcogdate with a good enantiomeric excess (Figure 5.17). 

Carboxycyclohexaneacetic acid, C-80023 1,2-Cyclopentanediol Di-Ac, in C-80189 1,1-Cyclopropanedicarboxylic acid Di-Et ester, in C-80196... 

Diphenyl-1,2-cyclopropanedicarboxylic acid Di-Et ester, in D-80509 Eupomatenoid 12, in E-60075 Isoxanthohumol/, 1-80100 Kurospongin, K-70015 Sandwicensin, in P-80076 Tephrinone, in G-70015 Tephrobbottin, T-70007... 

The monocyclopropylmethyl ester of phosphoric acid has been used for phos-phorylating nucleosides, and it provides a new and better route to nucleotides, since hydrolysis of the cyclopropylmethyl function can be readily effected in the range 2.5—2.8 pH units. Optically active polyamides have been produced from (- -)-(S)-trans-cyclopropanedicarboxylic acid. ... 

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