Methyl 2-Siloxycyclopropanecarboxylates Research Articles

Alkylation and Ring Opening of Perfluoroalkyl- and Perfluoroaryl-Substituted 2-Siloxycyclopropanecarboxylates Yielding Fluorinated γ-Oxo Esters or β,γ-Unsaturated Ketones

Deprotonation of perfluoroalkyl- and perfluorophenyl-substituted methyl 2-siloxycyclopropanecarboxylates and subsequent reaction with alkyl halides furnished C-1 alkylated cyclopropanes with high diastereoselectivities. Smooth triethylamine trishydrofluoride mediated desilylation and ring opening afforded the corresponding γ-oxo esters in good to excellent yields. Treatment of methyl 2-siloxycyclopropanecarboxylates with Grignard reagents and subsequent ring opening in the presence of acid provided β,γ-unsaturated ketones with fluorine-containing substituents.

ChemInform Abstract: A Novel Synthesis of Pyrrole Derivatives.

The enolates, generated from methyl 2-siloxycyclopropanecarboxylates, react with phenyl isothiocyanate (II)/methyl iodide (III) to give adducts which, after desilylation with Bu4N+F-, yield methyl 4,5-dihydro-1H-pyrrole-3-carboxylates.

Efficient and flexible syntheses of paraconic esters and other highly substituted furanone derivatives from methyl 2-siloxycyclopropanecarboxylates

Synthese des composes du titre par reaction des enolates de siloxy-2 cyclopropanecarboxylates de methyle avec des cetones suivie d'une decyclisation et d'une oxydation

ChemInform Abstract: Lewis Acid Promoted Additions of Cyclopropanes to Iminium Salts: A New Possibility for α‐Methylene‐γ‐butyrolactone Synthesis.

AbstractDas Iminiumchlorid (III) reagiert nach Überführung in das Triflat mit den Cyclopropancarbonsäureestern (II) zu den Amino‐oxo‐estern (IV), von denen (IVa) in die Methylenverbindung (V) sowie in die Lactone (VI) und (VII) übergeführt werden kann.

Lewis acid promoted additions of cyclopropanes to iminium salts: a new possibility for α-methylene-γ-butyrolactone synthesis

Methyl 2-siloxycyclopropanecarboxylates (1) smoothly add to dimethylmethyleneammonium trifluoromethanesulphonate, generated in situ, or to the corresponding minium chloride (4) in the presence of TiCl4, giving α-aminomethylated γ-oxoesters (6) in good yield; these can serve as precursors for α-methylene-γ-butyrolactones (7) as well as for acrylic ester derivatives (8).

Synthesis of functionalized furan derivatives by hydroxyalkylation of methyl 2-siloxycyclopropanecarboxylates

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.