52398-45-5Relevant academic research and scientific papers
Facile Synthesis of Some Substituted Methyl 3-Formylpropanoates
Bernard, Angela M.,Piras, Pier Paolo,Toriggia, Paola
, p. 527 - 529 (2007/10/02)
Variously substituted methyl 3-formylpropanoates are prepared in high yields by the reaction of methyl 4,4-dimethoxybutanoates with titanium tetrachloride.
Catalytic Hydrogenolysis of Methyl 2-Siloxycyclopropanecarboxylates: Investigations Regarding Chemoselectivity, Regioselectivity, and Stereoselectivity
Brueckner, Christiane,Reissig, Hans-Ulrich
, p. 617 - 626 (2007/10/02)
Alkyl-substituted methyl 2-(trimethylsiloxy)cyclopropanecarboxylates 8a - 8f are opened by hydrogen in the presence of palladium on carbon affording 4-oxoalkanoic esters 10a - 10e by desilylation. 2-Phenyl-substituted cyclopropanes 8g - 8j, however, provide 4-phenylbutanoic esters 13g - 13j under these conditions.Formation of 13j is not stereoselective.Here the primary cyclopropane cleavage is followed by hydrogenolysis of the benzylic C-O bond.This subsequent reaction can be suppressed in the case of 8g by poisoning the catalyst with triethylamine; otherwise the tert-butyldimethylsiloxy compounds 11g - 11i have to be used.Butanoic esters 14h and 14i, respectively, are formed as mixtures of diastereomeres, which is another indication for nonstereoselective hydrogenolysis of cyclopropanes.Whereas slow desilylation by hydrogen was observed with the 3-phenyl-substituted cyclopropane derivative 8k, the vinylcyclopropane 8m in part suffers cleavage of the 1-3 bond of the three-membered ring.Regio- and stereoselectivity of the hydrogenolysis of the donor-acceptor-substituted cyclopropanes 8 and 11 are discussed.
Ring Opening Reactions of Methyl 2-Siloxycyclopropanecarboxylates to Oxoalkanoic Acid Derivatives
Kunkel, Elisabeth,Reichelt, Ingrid,Reissig, Hans-Ulrich
, p. 802 - 819 (2007/10/02)
A great variety of methyl 2-(trialkylsiloxy)cyclopropanecarboxylates C1 - C31 are cleaved under very mild conditions and with excellent yields providing 4-oxoalkanoic esters D1 - D31 which are important synthetic building blocks.Even sensible esters with formyl, vinyl ketone, or trimethylsiloxy functions can be prepared.Corresponding to the regioselective synthesis of C isomeric pairs of D can deliberately be constructed.In the presence of an electrophile alkylating ring opening delivers 4-oxoalkanoates substituted in position 2, however, the degree of alkylation does not exceed 60percent.Several other cleavage variations allow syntheses of other 4-oxoalkanoic acid derivatives in effective one-pot procedures.
