19866-50-3Relevant articles and documents
Addition of diazomethane and sulfur ylides to the carbonyl group in derivatives of ketoses and aldoses-III. Reactions of 1,2-dideoxy-4,5-O-isopropylidene-d-glycero-3-pentulose
Hagen, Steinar,Lwande, Wilber,Kilaas, Lars,Anthonsen, Thorleif
, p. 3101 - 3105 (1980)
The reactions of diazomethane and dimethyloxo-sulfonium methylide with 1,2-dideoxy-4,5-O-isopropylidene-d-glycero-3-pentulose were studied. The sulfur ylide yielded two epimeric epoxides while diazomethane in addition furnished a homologous ketone. The reaction with diazomethane was carried out with varying concentrations of methanol in the reaction medium, and the relative yields of the three products were determined in each case. The results were explained on the basis of a two-step reaction mechanism proposed earlier. Steric effects and complexation between the positive nitrogen and one of the oxygens were inferred to be important.
Reaction of Diketene with Grignard Reagents in the Presence of Cobalt Catalyst. A Convenient Method for the Synthesis of 3-Methylenealkanoic Acids Leading to Terpenoids
Fujisawa, Tamotsu,Sato, Toshio,Gotoh, Yoshihiko,Kawashima, Masatoshi,Kawara, Tatsuo
, p. 3555 - 3559 (2007/10/02)
Primary alkyl Grignard reagents react regioselectively with diketene in the presence of cobalt(II) iodide to afford 3-methylenealkanoic acids in good yields.The synthetic utility of this reaction is demonstrated in the syntheses of terpenoids by two methods.Utilizing the isomerization of double bond of 3-methylenealkanoic acids, geranic acid and farnesic acid were obtained in two steps.Another method, the tandem sigmatropic rearrangement of the corresponding allylic esters was used for the synthesis of C18-Cecropia juvenile hormone.
