Aminocyclopropanes elimination

A variety of three-membered carbocycles including cyclopropylcarbonyl and -sulfonyl derivatives, cyclopropylcarbonitriles and -methanols, nitrocyclopropanes, cyclo-propanols and cyclopropylamines have been prepared via the 1,3-elimination of HX. Some representative cyclopropyl derivatives recently prepared by this method are shown in Scheme 116-18 and in equations 8-26. Conversion of chelated homoserine, 5,to chelated 2-amino-4-bromobutyrate and treatment with aqueous base directly affords chelated 1-aminocyclopropane-l-carboxylate (equation 8)19. The 1,3-elimination in 6 interestingly leads to the preferential formation of the cis isomer, from which 7, a key structural element of synthetic pyrethroid insecticides, is obtained (equation 9)20. A sulfur substituent can serve both as an activating group and as a leaving group in this type of reaction and, thus, 1,3-bis(phenylthio)propane affords cyclopropyl phenyl sulfide upon treatment with butyl-... 

Chemical signaling (Na and K in nerve cell membranes, Ca " in cell budding Fe(II), Cu(I) and other metal ions ligating transmitters such as NO, aUcenes in, e.g. regulation of flowering, fruit formation by ethylene (produced by oxidative elimination from 1 -aminocyclopropane-1 -carboxylate (Habermehl et al. 2003 Mengel and Zickermann 2007)), allyl formate or similar compounds)... 

Strongly basic nucleophiles such as an amide ion allowed a nucleophilic substitution via an elimination-addition mechanism of cyclopropane derivatives possessing an acidic hydrogen atom " ". Aminocyclopropanes 121 and 122 were synthesized in this manner from the corresponding halogenocyclopropanes " (equations 28 and 29). 

Elimination of a hydroxy anion to form a cyclopropyliminium ion is a typical reaction when 1-aminocyclopropanols are treated with acid. In the presence of carbon nucleophiles, trapping of the cyclopropiminium ion occurs (Table 14, entries 1-4). The overall transformation is substitution of the hydroxy group, hence providing a useful entry to a variety of 1-substituted aminocyclopropanes. Alkoxy- and (siloxy)aminocyclopropanes can also be used as substrates for this type of transformation (Table 14, entries 5 and 6). ... 

The reaction -will begin with the formation of a Schiff base between pyridoxal-5 -phos-phate and the amino group of 5-adenosylmethionine (external aldimine, as opposed to the internal aldimine in which PLP is connected to a lysine on the enzyme). In usual fashion for PLP enzymes, the a-hydrogen -will be extracted from S-adenosylmethionine (step 2, below). Then the next series of 7i-electron transfers (step 3) will eliminate S-methylthioadenosine and form the three-membered ring. Finally, f-aminocyclopropane-1-carboxylate (ACC) will be released, and the original internal aldimine between PLP and lysine veill be restored, so that the enzyme and cofactor are ready for another round of synthesis. The second product is S-methylthioadenosine. 

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