Novel One‐Step Synthesis of Oxocyclopentanecarboxylates by Electrochemical Reduction of Cinnamic Acid Esters

Abstract

When the experiment was carried out using the [2,4I3Cz]labeled isotopomer l a the following results were obtained : as expected, m / z 356 is quantitatively shifted to m / z 358, and its MWMS spectrum contains only a single signal at m / z 179 ( e 4a) after isotopic correction[41. The following conclusion can be drawn from this: Decarbonylation of 1 by electron impact ionization leads to an intermediate, which must be a derivative of ionized cyclobutadiene 2. Generation of a tetraphenyltetrahedrane radical cation 3, whose existence was postulated previouslyf5I, is completely inconsistent with the data obtained for l a . If the tetrahedrane intermediate 3a were really involved or a carbon scrambling of the C, moiety in the [M-CO]@' ion obtained from l a were to occur, then the distribution pattern shown in Scheme 1 should be observed in the formation of the ionized diphenylacetylene isotopomers (4, 4a, and 4b). This does not occur. The results are only compatible with route a and certainly exclude route b and isomerization c. A weak signal at m / z 180 (6%) can be attributed to incomplete ["C2]-labeling of l a . 38% of 1 is present as the ['3C,]-isotopomer, and the natural ["CI-abundance in the [M-COIQQ ion of this species gives rise to the formation of m / z 180. A signal at m / z 178 is not observed in the MS/MS spectrum of m / z 358. IS] M. M. Bursey, T. A. Elwood, Org. Mass Specrrom. I (1968) 531.

Cathodic reductive coupling of methyl cinnamate on boron-doped diamond electrodes and synthesis of new neolignan-type products

“…The GC electrode provided the coupling product 2 (34%, racemate/meso = 74:26) and E - 3 (25%), along with 41% of 1a . Similar cathodic reductions of cinnamate derivatives were carried out using Hg [ 10 – 11 ], Cu [ 12 – 13 ], Pb [ 13 – 14 ], Zn [ 13 ], Sn [ 13 ], and Ag [ 13 ], and the major products were the cyclic products (type 3 ) through Diekmann-type cyclization, whereas the hydrodimer 2 was the predominantly produced product in the present BDD electrode mediated reduction. Despite a different product ratio, the GC electrode gave similar reaction products to that of the BDD electrode.…”

Hydroxylated HMPA Enhances both Reduction Potential and Proton Donation in SmI2 Reactions

“…The combined organic layer was washed with 5% aqueous phosphate buffer solution (2 × 10 mL) and brine solution (20 mL) and dried over anhydrous Na 2 SO 4 . After removal of the solvent under reduced pressure, the crude reaction mixture was purified by column chromatography on silica gel (60–120 mesh) using 10% ethyl acetate in petroleum to afford pure product (73.0 mg) in 62% yield as a white solid: mp 122–124 °C (lit . mp 126 °C), analyzed by 1 H (700 MHz) and 13 C (175 MHz) NMR and mass spectra.…”