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Short-lived (f 1/2 < 10-3 sec) anion radicals of activated olefins (CH2=CHX with X = CO2CH3, CN, and acetyl) generated at a mercury cathode under anhydrous conditions react rapidly with carbon dioxide. Further reduction of the radical carboxylate intermediate and subsequent carboxylation results in the formation of substituted succinic acid derivatives. An alternate pathway involves electroreduction of carbon dioxide and subsequent reactions

buret. The rate of addition was such that a maximum current of 0.6 A was passed. The electrolysis was discontinued when the current had fallen to 0.05 A. For cie experiments 0.07 mol of the olefin was taken up in acetonitrile (total volume of 25 ml) and the solution was added to the catholyte at a rate equivalent to 5.6 X 10~3 mol/hr with a syringe pump. A constant current of 0.3 A was maintained [i.e., 0.3 A = (53.6 A hr/mol)(5.6 X 10~3 mol/hr)]. The catholyte was continuously saturated with C02 during the electrolyses. The cathode potential was monitored with a see.General Electrolysis Procedure. Monocarboxylation. The apparatus employed is shown in Figure 3. The top layer of propionitrile [0.06 M in (CiHg^N+BFu and 2.8 M in H20] was circulated through the cell while being saturated with 100% CO2 for 15 min prior to starting the electrolysis. Acrylonitrile was then added at a rate of 2.43 g/hr to the circulating propionitrile electrolyte solution (continuous C02 saturation). A constant current of 2.35 A was maintained [i.e., 2.35 A = (53.6 A hr/mol)(4.38 X 1CH2 mol/ hr)].Work-Up and Analyses of Catholytes. The products of electrocarboxylation under anhydrous conditions were converted to their methyl esters by treating the catholyte solution directly with an excess (0.28 mol) of methyl iodide at ice-bath temperatures (c/.footnote c of Table II). The acetonitrile and excess methyl iodide were removed and the organic products were separated from the electrolyte by benzene-water extraction. If authentic samples were available, analyses were done directly on the benzene-soluble material by glc (internal standards), using one of the following columns and conditions: (a) 6 ft X 0.125 in. S.S. 3% OV-101 on Chromosorb W (80-100 mesh), 150 -» 280°at 10°/min; (b) 10 ft X 0.125 in. S.S. 5% FFAP + 1% Carbowax 20M on Chromosorb G (80-100 mesh), 100 -200°at 10°/min; (c) 10 ft X 0.125 in. S.S. 3% QF-1 on Gas Chrom Q (60-80 mesh), 100 -* 200°at 10°/min. Products for which authentic samples were not available were isolated by distillation and/or preparative glc. The following column and conditions were used: 3 ft X 0.75 in. S.S. 30% FFAP + 6% Carbowax 20M on Chromosorb W (60-80 mesh), 200°. The products so obtained were subsequently used for yield determinations by glc (internal standards). Yield data for electrocarboxylations under partially aqueous conditions were obtained by analyzing the aqueous extract by nmr using sodium acetate as an internal standard.Identification of Products. Products were confirmed by comparing their glc retention lines, mass spectra, nmr spectra, and boiling points. New compounds were identified by their mass spectra, nmr spectra, and elemental analyses. These compounds and the appropriate analytical data are given in Table III.

It is shown that in mixed reductive coupling of activated olefins A and B, in which A is reduced at the more anodic voltage, the ratio of cross‐coupled product HABH to self‐coupled product HAAH rises substantially as the controlled potential is made more negative. Diethyl maleate (DEM) was chosen as an example of A and ethyl acrylate (EA) and acrylonitrile (AN) as examples of B. Previously reported fluctuations of voltage along the cathode surface are confirmed and may lead to unexpected formation of HBBH. The results of cyclic voltammetry of DEM in the presence of EA or AN and of a kinetic study of the addition of a carbanion to these same acceptors in bulk are interpreted to indicate that the reductive coupling of DEM with the acceptors occurs largely but not exclusively at the electrode surface.

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Studies of the acid-catalyzed hydrolysis of phosphinanilides demonstrate that protonation has a profound labilizing effect on P-N bonds. In H2S04: -V-(p-nitrophenyl)diphenylphosphinamide exhibits a kinetic dependence on A0 with rate law, v = k[amide]/io° 9, and nonlinear dependence of log k on log [acid]. Examination of the dependence of the rate constants on acidity functions indicates an Ai mechanism: application of the Zucker-Hammett or Bunnett methods requires an acidity function which correctly describes the protonation behavior of the substrate-when log k is plotted vs. Ha, the acidity function for amides, a straight line with slope 1.0 results. This analysis of the dependence of rate on acidity and the large solvent isotope effect, kfk-= 2.8, provides strong evidence for an Ai mechanism. The variation in rate with TV-aryl substituents, p = -1.7, is consistent with a tran-Amer. Chem. Soc., 94,9260 (1972).

No abstract

The angle strain present at phosphorus in small rings is known to produce large accelerations in rates of displacement at phosphorus.2 These results are important evidence for displacement through a pentacoordinate intermediate in which pseudorotation is possible. We now report two cases in which the same structural effect results in a very large inhibition in rate of displacement at phosphorus. The contrasting effects enable discrimination between associative displacement through a pentacoordinate intermediate and an SN2-like direct displacement mechanism.There has recently been great interest in the fourmembered ring (1) which is readily available.3 This ring system has a twofold effect. (1) The four amethyl groups provide considerable steric hindrance.(2) The C-P-C angle is approximately 83°. This provides a considerable driving force for formation of pentacoordinate intermediates in which strain can be released.2 These effects appear in the esters 1 (X = OCH3, OC2Hs) which undergo alkaline hydrolysis with displacement at phosphorus4 at a rate which is como o (ch^ch-p-x