Acetoacetates Reformatsky reaction

The first three retrosynthetic cleavages are formation of the C7-C8 aldol by intramolecular chromium-Reformatsky reaction of linear precursor 51, esterification between northern and southern half building blocks and Wit-tig reaction of phosphonium salt 52 known from Mulzer s work [85] and northern half precursor 53. The final disconnections were placed at the C2-C3 aldol in 51 (again to be formed by chromium-Reformatsky reaction, here between bromoacetimide 56 and aldehyde 57) and the C14-C15 bond by alkylation of acetoacetate 54 with neryl bromide 55. 

Ediyl acetoacetate gave only low yields in a Reformatsky reaction but even this is remaikable considering its acidic nature (equation 17). 3 Keto esters that lack acidic hydrogens react in good yield (equation 18). ... 

The Reformatsky reaction with A(-acyloxazolidin-2-ones and -thiazolidin-2-thiones provides a route to /3-keto esters. The electrolysis of a-bromoalkanoic esters in acetonitrile on a zinc anode with ZnBr2 and Bu NBEi as supporting electrolytes gives acetoacetic ester derivatives. The acetonitrile solvent is partially consumed. 

Diastereoselective a-alkylations of acetoacetic acid derivatives <1995T10795> and amino acid aldimines 582 (R = GOG(R )N=GHAr) <1995TL4069> were reported. Tandem Reformatsky and Mannich-type reactions provide an efficient diastereoselective synthesis of /3-amino acids <2006JOG3332>. 

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