Diethyl -2,3-epoxysuccinate

The double bonds in diethyl maleate and fumarate are very electron deficient olefins. These were indeed the most difficult compounds to epoxidize. The usual treatment with slight excess of oxidant for short periods of time did not result in any reaction. With a large excess, however (5-10 molequivalent) progress could be monitored at room temperature and after 12 hours about 90% conversion was achieved. Thus cis and traits diethyl epoxysuccinate were obtained in 65% and 50% yield respectively. These epoxides are important intermediates in many syntheses, immuno-pharmacological studies and polymerization processes and are always made stepwise by indirect methods. A full retention of configuration was observed and neither epoxide was contaminated with the other (figure 12). 

Diethyl (2R,3R)-2,3-epoxysuccinate 2,3-Oxiranedicarboxylic acid, diethyl ester, (2R-trans)- (10) (74243-85-9)... 

Diethyl D-tartrate (2b), treated similarly with 30% hydrobromic acid in acetic acid followed by acidic hydrolysis, is converted to diethyl 6 y /fro-(2R,3R)-2-bromo-3-hydroxysuccinate (824) in an overall yield of 73%. Sodium ethoxide cylization affords (2 S, 3 S)-2,3-epoxysuccinate (825), which is the enantiomeric epoxide of 821. Epoxide cleavage with lithium dimethylcuprate provides in 78% yield diethyl (2S,3R)- eo /zro-3-methylmalate (826), which is converted in eight steps to ( —)-(l S, 2 S, 4iS, 5R)-2,4-dimethyl-5-ethyl-6,8-dioxobicyclo-[3.2.1]octane or ( —)-(5-multistriatin (827), one of the eight possible stereoisomeric forms for this pheromone component responsible for the aggregation of the North American... 

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