Eine flexible Synthese von 4-Oxobutansäure- methylestern und deren Derivaten
作者:Thomas Kunz、Agnes Janowitz、Hans-Ulrich Reißig
DOI:10.1055/s-1990-26783
日期:——
A Flexible Synthesis of Methyl 4-Oxobutanoates and Their Derivatives Ring cleavage of several methyl 2-trimethylsiloxycyclopropanecarboxylates 3 provides rather sensitive methyl 4-oxobutanoates (ß-formyl esters) 4 in excellent yields. Siloxycyclopropanes 3 are easily available either directly from the corresponding silyl enol ethers 2 and methyl diazoacetate or by alkylation of deprotonated cyclopropanes 3. A highly efficient one-pot procedure affords methyl 4,4-dimethoxybutanoates 5, which can be converted into protected 4-hydroxybutanals 7 and 8 by standard methods.
Synthesis of functionalized furan derivatives by hydroxyalkylation of methyl 2-siloxycyclopropanecarboxylates
作者:Christiane Brückner、Hans-Ulrich Reissig
DOI:10.1039/c39850001512
日期:——
A variety of methyl tetrahydrofuran-3-carboxylates (4) or the 5-oxo analogues (6) are available in good overall yield by deprotonation of cyclopropanes (1), addition of carbonyl compounds, ring cleavage, and reductive or oxidative work-up, respectively.