Shikimate. methyl

Nucleophilic additions to (cyclohexadienone)Fe(CO)3 complexes (218) occur in a dia-stereospecific fashion (Scheme 56)197. For example, the Reformatsky reaction of ketone (218a) affords a simple diasteromeric alcohol product19715. The reduction of (1-carbo-methoxycyclohexa-l,3-dien-5-one)Fe(CO)3 (218b) to give 219 has been utilized in the enantioselective synthesis of methyl shikimate. In a similar fashion, cycloadditions of (2-methoxy-5-methylenecyclohexa-l,3-diene)Fe(CO)3 (220) occur in a diastereospecific fashion198. 

McGowan, D. A. Berchtold, G. A. (-)-Methyl cis-3-hydroxy-4,5-oxycyclo-hex-l-ene carboxylate Stereospecific Formation from and Conversion to (-)-Methyl Shikimate Complex Formation with Bis(carbomethoxy)hydra-zine, J. Org. Chem. 1981,46, 2381. 

As an example of conversion of complex 111 to 113, optically pure complex 126 was used for the enantioselective total synthesis of shikimic acid (129) [30]. The hydroxy-substituted diene complex 127 was prepared from 126. Silylation and decomplexation of 127 gave 128. Stereoselective dihydroxylation of the more reactive double bond of the decomplexed silyl ether derivative 128, followed by desilylation afforded (—)-methyl shikimate (129). 

Protection of 194 as a p-methoxybenzylether and subsequent epoxydation led to the trans-epoxide 195, which was transformed into the unsaturated aldehyde 196 by a three-reaction sequence, including regioselective oxirane opening with a 1,3-dithiane anion, hydrolysis of the dithioacetal formed, and dehydration. Chlorite promoted aldehyde oxidation, methyl ester formation, and removal of the hydroxyl protections delivered methyl (+)-shikimate 197 in a remarkable 12% yield from 193. 

Prtvost reaction. A short synthesis of methyl shikimate (5) involves base-promoted cleavage of 1, obtained by a Diels-Alder reaction of furane with methyl acrylate (11,... 

Mirza, S., and Vasella, A., Deoxy-nitrosugars. Part J. Synthesis of methyl shikimate and of diethyl phosphashikimalc from D-ribose, Helv. Chim. Acta, 67, 1562, 1984. 

Methyl shikimate 116 has been made using a strategy with iodolactonisation at its heart.26 Note that shikimate has three chiral centres. Interestingly, these three centres are controlled in the synthesis by a centre that is finally destroyed. The first steps are iodolactonisation of 103 and subsequent elimination and epoxidation to give 109 as described above. 

Epoxide 109 is opened with Me3SiBr (Ph3P-catalysed) and another elimination with DBU gives the allylic alcohol 117. The epoxidation that follows is controlled in a couple of ways. Firstly, the axial alcohol can direct the reagent (the same peroxyacid used to make 109) to the bottom face of the six-membered ring which is also the less hindered side of the molecule (opposite the lactone bridge) 118. The synthesis is completed with basic methanolysis of the lactone 118 to give racemic methyl shikimate 116. 

Brief synthesis of ( )-methyl shikimate, ( )-methyl epishikimate and structural variants. Tetrahedron 40 2461-2470. 

As a more practical route to EPSP, we elected to pursue a partial synthesis, starting with methyl shikimate acetonide (20) which is readily available from shikimic acid itself. While our work on this transformation was in progress,... 

Nucleophilic attack by bicarbonate onto a dienyl complex 10.118 with an ester substituent also proceeded regioselectively. Starting from the resolved complex, methyl shikimate 10.122 could be prepared in optically active form using this reaction (Scheme 10.30). Protection of the alcohol and decomplexation gave the free diene 10.121, which underwent selective dihydroxylation trans to the TBS ether. Desilylation gave the natural product ester 10.122. 

Both (-)-shikimate-3-phosphate and quinic acid 3-phosphate have been synthesized by standard chemical transformation from methyl shikimate and quinic acid respectively. ... 

Both enantiomers of methyl shikimate have been obtained following microbial oxidation of benzene. "... 

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