Acetoacetic 4-bromo-, ethyl ester

CsHsBrOs 4-bromo-acetoacetic acid ethyl ester 13176-46-0... 

A biomimetic synthesis of (-)-xestospongin A (116), (+)-araguspongine B (129), and (+)-xestospongin C (130) was developed (Scheme 12) [43], starting from a Weiler s alkylation of ethyl acetoacetate (131) with 1-bromo-4-chlorobutane (132) to give the ethyl ester of 8-chloro-3-oxooctanoate... 

The patent describes the formation of complex metal chelates by treatment of the ketoester simultaneously with an alcohol and a metal to effect trans-esterification and chelate formation by distilling out the by-product ethanol [1], This process was being applied to produce the zinc chelate of 2-tris(bromomethyl)ethyl acetoacetate, and when 80% of the ethanol had been distilled out (and the internal temperature had increased considerably), a violent decomposition occurred [2], This presumably involved interaction of a bromine substituent with excess zinc to form a Grignard-type reagent, and subsequent exothermic reaction of this with one or more of the bromo or ester functions present. 

The reaction of a-bromo-a,/8-unsaturated esters and butenolides with ethyl acetoacetate has been shown to proceed stereoselectively to give the c -fused reduced furan (73). The butenolides are more accessible than the sulphur... 

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