Ethyl acetoacetate: alkylation coupling reaction

C2]-Squalene, 80, has been produced71 in the reaction sequence shown in equation 31 which involves alkylation of 3-13C-ethyl acetoacetate with geranyl bromide, followed by hydrolysis, decarboxylation and treatment with triethyl phosphonoacetate and then reduction of the ester 82 with LiAlHr, bromination with CBr4/PPh3 and coupling the farnesyl bromide with Cul/Li-pyrrolidine. Epoxidation of 80 has been effected by... 

Reddy et al. synthesized 5-hydroxyindole derivatives via the Nenitzescu reaction by coupling of aniline, ethyl acetoacetate, and p-benzoquinone, in 1,2-dichloroethane, using montmorillonite KSF clay as catalyst (Scheme 18) [87]. The reaction was also performed using acyclic and cyclic 1,3-diketones and with aryl and alkyl amines. Among several catalysts tested in this reaction, montmorillonite KSF clay proved to be the best catalyst leading to the highest yields in a shorter reaction time. 

The first steps of the [ C]squalene synthesis resemble the pathway selected for the synthesis on [3 - C]coenzyme QIO 13061 (Figure 6.84). In this case alkylation with solanesyl bromide (3011 and subsequent hydrolysis and decarboxylation of the ester function converted ethyl [3- C]acetoacetate into [2- C]solanesylacetone 302. Chain extension of 302 in a Homer-Wadsworth-Emmons reaction, reduction of the resulting a,/3-unsatu-rated ester 303 and coupling of the resulting alcohol ([3- C]decaprenol, 3041 to 2-methyl-5,6-dimethoxy-1,4-hydroquinone (3051 provided the coenzyme in an overall radiochemical yield of 8% after oxidation. Methodologically comparable pathways have also been published for the synthesis of [5- C]farnesylacetic acid and [3 - C]menaquinone . 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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