bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enolization and oxidation: IV. Iron ion catalyzed autoxidation of acetoin
Authors: van den Besselaar A. M. H. P. , Lubach J. , Drenth W. 
Published: September 2010

AbstractThe catalytic effect of iron(III) and iron(II) perchlorate on the autoxidation of acetoin (3‐hydroxy‐2‐butanone) has been studied in perchloric acid solution ranging from 0.125 to 2 mol/1. The experiments have been carried out in water and in aqueous ethanol 1: 1 v/v. A mechanism is presented in which the formation of an intermediate iron(III) enolate is the slow step. In subsequent steps the enolate is oxidized either by iron(III) or by oxygen. In the latter case simultaneous oxidation of iron(II) probably occurs.Starting from iron(III) as well as from iron(II) a steady state is reached in which the ratio Fe(III)/Fe(II) is in the order of 100.
A novel route for the synthesis of 1‐benzoxepins and some of their reactions
Authors: Reinhoudt D. N. , Kouwenhoven C. G. 
Published: September 2010

AbstractA 1‐benzoxepin has been synthesized in high yield by cycloaddition of 3‐pyrrolidinobenzofuran to dimethyl acetylenedicarboxylate, followed by thermal rearrangement of the [2 + 2] cyclo‐adduct. A kinetic study of the isomerization revealed that the ring opening occurs via a highly polarized transition state and that this rapid reaction is favoured by the electron‐donating capacity of the pyrrolidino substituent. Hydrolysis of the pyrrolidino group and subsequent reaction afford several 1‐benzoxepin derivatives. At elevated temperatures the 1‐benzoxepins undergo rearrangement to 1‐naphthol derivatives, the rate of which greatly depends on the electron density of the oxepin ring. Upon irradiation the 1‐benzoxepins are readily converted into 2a,7b‐dihydrocyclobuta[b]benzo‐furans.
The reactions of 3‐bromo‐ and 4‐bromo‐1,6‐naphthyridine and of 3‐chloro‐ and 4‐chloro‐1,6‐naphthyridine with potassium amide in liquid ammonia
Authors: Czuba W. , Woźniak M. 
Published: September 2010

AbstractMixtures of 3‐amino‐ and 4‐amino‐1,6‐naphthyridine were obtained from both 3‐bromo‐and 4‐bromo‐1,6‐naphthyridine on amination with potassium amide in liquid ammonia. Similar results were obtained with the corresponding chloro derivatives. The relative yields of isomeric amino derivatives indicate that the reaction mechanism involves not only the formation of 3,4‐didehydro‐1,6‐naphthyridine but also simple addition‐elimination (AE).
C‐Alkylations of cyclic 1,3‐diketones
Authors: de Groot Ae. , Jansen B. J. M. 
Published: September 2010

AbstractSeveral cyclic 1,3‐diketones can be alkylated at C‐2 in very high yields with ethyl 2‐(bromomethyl)acrylate or diethyl (bromomethyl)maleate. A mechanism involving initial O‐alkylation followed by a Claisen rearrangement to give the C‐alkylated product is proposed.
Cyclobutadienyl dications as intermediates in the rapid degenerate rearrangements of 4‐halo‐1,2,3,4‐tetrasubstituted cyclobutenyl cations
Authors: van der Hout‐Lodder A. E. , de Haan J. W. , Buck H. M. 
Published: September 2010

AbstractBased on 13C NMR chemical shifts at variable temperatures it is suggested that cyclobutadienyl dications form essential intermediates in the rapid equilibration of 4‐halo‐1,2,3,4‐tetrasubstituted cyclobutenyl cations.
A new method for the preparation of homoaromatic cations: 1‐methoxycyclooctatrienylium cation
Authors: de Dobbelaere J. R. , Buck H. M. 
Published: September 2010

AbstractThe 1‐methoxycyclooctatrienylium ion has been prepared from 7,7‐dimethoxy‐1,3,5‐cyclooctatriene by reaction with PCl5 or SOCl2 in liquid SO2.
Poly(ethylenimine) II. Potentiometric titration behaviour in comparison with other weak polyelectrolytes
Authors: van Treslong C. J. Bloys , Staverman A. J. 
Published: September 2010

AbstractPotentiometric titration data of poly(ethylenimine) (PEI) and poly(vinylamine) (PVA) are presented. They are described in a phenomenological way by the procedures of Henderson‐Hasselbalch and Mandel, respectively and the conforming parameters are calculated. The values of the parameters are compared for the two polymers mutually and with literature data for other weak polyelectrolytes. Marked specific differences are indicated. These are explained in a qualitative way from the nature of the ionizable group and structure of the polymers. A more quantitative explanation will be attempted in a following paper.
Mechanism of the action of potassium amide in liquid ammonia on 2‐bromopyridine
Authors: den Hertog H. J. , Boer H. , Streef J. W. , Vekemans F. C. A. , van Zoest W. J. 
Published: September 2010

AbstractEvidence is presented that 2‐bromopyridine is converted by potassium amide in liquid ammonia into 2‐aminopyridine by the addition‐elimination (AE)‐mechanism and not by an EA‐transformation via a didehydropyridine, the “ANRORC”‐mechanism (= subsequent addition of the amide ion to C‐6, ring‐opening with elimination of the bromide ion and ring‐closure) or an abnormal AE‐mechanism (starting with the addition of an amide ion to C‐6).
Potassium bis(3‐phenylbiuretato)cobaltate(III).2DMSO. The crystal structure of a spin triplet cobalt(III) complex, containing dimethyl sulfoxide
Authors: Birker P. J. M. W. L. , Beurskens P. T. 
Published: September 2010

AbstractThe structure of potassium bis(3‐phenylbiuratato)cobaltate(III), crystallizing with two molecules of dimethyl sulfoxide, KCo(HNCON(C6H5)CONH)2.2(CH3)2SO, was determined by X‐ray analysis. The crystals are monoclinic, space group P2/c, with unit cell dimensions a = 7.471 ± 0.014, b = 8.126 ± 0.017, c = 21.467 ± 0.036 Å, β = 95.29° ± 0.13, and two formula units per unit cell. 2286 reflections were measured with an automatic diffractometer. The structure was refined by full matrix least squares methods. For 1019 reflections with I > 1½ σ (I), R = 0.14; for 638 reflections with I > 3 σ (I), R = 0.10. The complex anion is situated on a twofold symmetry axis. The cobalt atom is in almost planar N4‐coordination, with CoN bonds of 1.83 and 1.84 Å. The two DMSO molecules are not coordinated with the cobalt atom, but they are incorporated in the lattice with their oxygen atoms coordinated with the potassium ions.
Chemistry of acetylenic ethers 107. Synthesis of 1,4‐thiaphosphorins and 1,4‐thiarsenins
Authors: Schoufs M. , Meijer J. , Vermeer P. , Brandsma L. 
Published: September 2010

Abstract1,4‐Thiaphosphorins and 1,4‐thiarsenins (2) have been obtained by addition of phenylphosphine and phenylarsine to di‐l‐alkynyl sulfides under catalytic influence of lithium amide in liquid ammonia.
Bis(tricyclohexylphosphine) complexes of group VI transition metals
Authors: Moers F. G. , Reuvers J. G. A. 
Published: September 2010

AbstractThe reaction of M(CO)6 or M(CO)3L (MCr, Mo or W) with tricyclohexylphosphine (PCy3) yield trans‐M(PCy3)2(CO)4. Cis‐compounds could not be detected by infrared and raman spectroscopy. All attempts to prepare complexes in which more than two PCy3 groups are coordinated to the metal by reaction with an excess of PCy3 were unsuccessful.
Mechanisms of reactions of 3‐bromopyridine 1‐oxide and derivatives with potassium amide in liquid ammonia
Authors: Peereboom R. , den Hertog H. J. 
Published: September 2010

Abstract3‐Bromopyridine 1‐oxide and some of its derivatives react with potassium amide in liquid ammonia by the elimination‐addition [SN(EA)] mechanism. It depends on the character and the position of the substituent whether the pathway via 2,3‐ or 3,4‐didehydropyridine 1‐oxide is followed. In the amination of 3‐bromoquinoline 1‐oxide a remarkable side‐reaction occurs.
On the occurrence of an SN(ANRORC) mechanism in the amination of 2‐substituted 4‐phenylpyrimidines with potassium amide in liquid ammonia
Authors: Kroon A. P. , van der Plas H. C. , van Garderen G. 
Published: September 2010

AbstractOn amination of 2‐X‐4‐phenylpyrimidine [X = SCH3, SO2CH3, SC6H5, SO2C6H5, SCN, CN, \documentclass{article}\pagestyle{empty}\begin{document}$\rm{N}^\oplus $\end{document}(CH3)3] with potassium amide in liquid ammonia at ‐ 33° and/or ‐75°, 2‐amino‐4‐phenylpyrimidine is in general formed as the main product. Depending on the substituent in position 2, several by‐products are formed: when X is \documentclass{article}\pagestyle{empty}\begin{document}$ \rm{N}^\oplus $\end{document}N(CH3)3, some bis(4‐phenyl‐2‐pyrimidinyl)amine is obtained; in the case of X = SCN. a considerable amount of (4‐phenyl‐2‐pyrimidinyl) disulfide is formed, while for X = SCH3 and SC6H5, 3‐amino‐3‐phenylacrylonitrile is produced. It is proved, using 2‐X‐4‐phenyl‐[1,3‐15N]‐pyrimidines, that the formation of the 2‐amino compound can occur by a ring opening/ring closure sequence [SN(ANRORC) mechanism]. The percentage of the compounds which react by this mechanism is found to be 91% for X = SCH3, 73% for X = SO2CH3, 34% for X = SO2Ph, 90% for X = SCN, 5% for X = CN and 10% for X = \documentclass{article}\pagestyle{empty}\begin{document}$ \rm{N}^\oplus $\end{document}N(CH3)3. By PMR spectroscopy of solutions of 2‐X‐4‐phenylpyrimidine (X = SCH3 and SO2CH3) in liquid ammonia, containing potassium amide, good evidence is found for the presence of Meisenheimer σ‐adducts, formed by an addition of the amide ion to C(6) of the pyrimidine ring.
Interrelations of unsaturated aliphatic compounds I. General considerations
Authors: Arens J.F. 
Published: September 2010

AbstractGraphs depicting the interrelations of unsaturated systems (eliminations, additions, substitutions and isomerizations) are presented.Such graphs are suitable frameworks for interrelation studies, especially for tele reactions (a large group of reactions occurring at the ends of conjugated systems and involving only a change of hybridization of the terminal atoms).
The reactions of salicylaldehydes and 2,2‐diary 1‐2H‐chromenes with 1,1‐bis[p‐(dimethylamino)phenyl] ethylene; photochromic chromenes
Authors: Zwanenburg D.J. , Maas Th. A. M. M. 
Published: September 2010

AbstractThe reactions between 1,1‐bis(p‐dimethylaminophenyl)ethylene (Michler's ethylene) (5) and salicylaldehydes (6) were studied for the purpose of synthesizing photochromic chromenes (1). Although we proved the presence of the chromene 1 under some conditions, the only compounds we could isolate were the so‐called “disubstitution products” 7. Reaction of 2,2‐bis[p‐(dimethylamino)‐phenyl]‐2H‐chromene [1a, synthesized by a Grignard reaction of coumarin with p‐(dimethylamino)‐phenylmagnesium bromide] with Michler's ethylene also gives the “disubstitution product” 7a. Reactions of Michler's ethylene with 2,2‐bis(p‐methoxyphenyl)‐2H‐chromene (3) and the spiropyran 11 furnished the “mixed disubstitution products” 9 and 10, respectively. A reaction of the latter with 5‐nitrosalicylaldehyde gives 2,2‐bis[p‐(dimethylamino)phenyl]‐6‐nitro‐2H‐chromene 1b. The photochromism of the synthesized chromenes is described briefly.
Photochemistry of pyrimidine N‐oxides (IV)
Authors: Roeterdink F. , van der Plas H.C. , Koudijs A. 
Published: September 2010

AbstractPhotolysis of 2,4,6‐trimethylpyrimidine 1‐oxide in methanol with light of 254 nm leads to rearrangement into 4(5)‐acetyl‐2,5(4)‐dimethylimidazole and 1,2,4‐trimethyl‐1,6‐dihydro‐6‐oxopyrimidine. In benzene only the formation of the imidazole and an unknown compound X is observed. In both solvents the products are formed from the same primary photoproduct. Ring contraction into an imidazole also takes place on ultraviolet irradiation of 4‐chloro‐2,6‐dimethylpyrimidine 1‐oxide in benzene and of 2,6‐dimethyl‐4‐methoxypyrimidine 1‐oxide in methanol. Results of conventional flash photolysis applied with the aim of getting some information about the intermediary formation of oxaziridines are inconclusive. The role of possible intermediates ‐ oxaziridines, 1,2,4‐oxadiazepines or zwitter ionic species ‐ in these rearrangement reactions is discussed.
Réactivité des germylamines vis à vis de quelques composés α ou β dicarbonylés
Authors: Rivière‐Baudet M. , Satgé J. 
Published: September 2010

AbstractThe trialkylgermylamines R3GeNR′2, condense by 1‐2 dipolar addition on to one of the carbonyl groups of α‐diketones, such as biacetyl or benzil, leading to α‐amino β‐oxoalkoxygermanes. Dialkylbis(dimethylamino)germanes, R2Ge(NR′2)2 also, lead to an insertion derivative on to one of the carbonyl groups of biacetyl or benzil, but the expected 4,5‐bis(dimethylamino)‐2‐germa‐1, 3‐dioxolane is not obtained.All the α‐amino β‐oxoalkoxygermanes formed in the course of these reactions are thermally unstable. The decomposition proceeds by an intermolecular mechanism, observed previously for α‐amino β‐oxoalkoxygermanes and leads, in the case of amine R3GeNR′2 to an α‐ketoenamine and in the case of R2Ge(NR′2)2 to a diaminodiene.In the reaction between acetylacetone and (triethylgermyl)dimethylamine, without a solvent, only 1,2 dipolar addition on one of the carbonyl groups of the reagent is observed, to the exclusion of cleavage of the Ge‐N bond. In the same reaction carried out in hexane, Ge‐N bond cleavage by the enolic form of acetylacetone is observed; nevertheless, the formation of a 1‐2 addition derivative on to the carbonyl group still preponderates.The α‐amino β‐oxoalkoxygermanes formed are thermally unstable and the decomposition by an intramolecular mechanism proceeds by coordination between oxygen of the Ge‐O‐C group and hydrogen of the methylene group in α position to carbonyl.
Reversible halogenation of cyanine dyes
Authors: van Beek H. C. A. , Hendriks C. H. F. , van der Net G. J. , Schaper L. 
Published: September 2010

AbstractThe reaction of bromine or iodine with cyanine dyes results in the formation of an equilibrium mixture of the dye and the halogen used, their 1: 1 addition product, the mesohalogen derivative of the dye, the 1: 1 addition product of the latter and the halogen used, the protonated dye and its dimeric or polymeric forms. The equilibrium constants of the different reactions are presented. The original dyes are easily regenerated from the halogenated products if other halogen acceptors are present in the system. The processes described can be of importance in the chromatic sensitization of photographic materials.
11‐Alkylidene steroids in the 19‐nor series
Authors: van den Broek A. J. , van Bokhoven C. , Hobbelen P. M. J. , Leemhuis J. 
Published: September 2010

AbstractA number of 11‐methylene‐substituted estrenes and 19‐nor‐pregnenes have been synthesised. In addition, some 11‐(E)‐ethylidene estrenes have been prepared. Evidence is presented establishing the configuration of the ethylidene substituent.
A new synthesis for 1,3‐dichloro‐2‐propanone
Authors: Nollet A. J. H. , Ladage J. W. , Mijs W. J. 
Published: September 2010

AbstractA new synthesis for 1,3‐dichloro‐2‐propanone (symm‐dichloroacetone) is described using diketene and chlorine as starting materials. The chlorination product of diketene, 2,4‐dichloro‐3‐oxobutyryl chloride, was converted into the corresponding butyric acid derivative. Subsequent decarboxylation by heating gave 1,3‐dichloro‐2‐propanone in 77% overall yield, without isolation of intermediate products.
Hydrobenzothiopyran‐4‐one S,S‐dioxides. Synthesis and structural elucidation
Authors: Kattenberg J. , de Waard E.R. , Huisman H.O. 
Published: September 2010

AbstractThe synthesis of hexa‐ and octahydrobenzothiopyran‐4‐one S,S‐dioxides 1–4 is described. The regioselective and stereospecific H/D‐exchange of the hydrogens α to the SO2 group is accomplished by careful control of reaction conditions. The comparison of the PMR spectra of the deuterio and protio derivatives allows the establishment of the mode of ring fusion.
Poly(vinylamine). Synthesis and characterization
Authors: van Treslong C. J. Bloys , Morra C.F.H. 
Published: September 2010

AbstractA number of poly(vinylamine) (PVAm) samples with different molecular weight were synthesized following basically the same method as described by Hart. For PVAm and the intermediate macromolecular product, poly(tert‐butyl vinylcarbamate) (PBVC), relations between the limiting viscosity number [η] and the number average molecular weight as determined by osmotic measurements are proposed. For two high molecular weight samples of PVAm also the weight average molecular weight was determined by light‐scattering measurements.
A versatile synthesis of allenic hydrocarbons. Evidence for an organocopper(III) intermediate
Authors: Vermeer P. , Meijer J. , Brandsma L. 
Published: September 2010

AbstractA number of allenes RR1CCCHR2 2 have been prepared by interaction between acetylenic tosylates R1C≡CCHR2OTs, 1 (R1 = H, alkyl, aryl, H2CC(CH3) or CH3C≡C; R2 = H or t‐C4H9) and organocopper(I) compounds “RCu” (formed from Grignard compounds RMgCl or RMgBr with R = alkyl, aryl or 2‐thienyl and copper(I) bromide in tetrahydrofuran). If R = t‐C4H9 the reaction with catalytic amounts of CuBr also gives good results. Significant amounts of C6H5CHCCH2 or C6H5CDCCH, are formed if C6H5CCCH2OTs is reacted with “CH3Cu” (from CH3MgCl and CuI) at −60° in tetrahydrofuran and the reaction mixture is quenched at low temperatures with methanol or deuteriomethanol. This finding is considered as evidence for the intermediate occurrence of a copper(III) derivative.
Conformation of non‐aromatic ring compounds — 92 Carbon‐13 nuclear magnetic resonance spectra of some 3‐arylglutaric anhydrides
Authors: Koer F.J. , Altona C. 
Published: September 2010

AbstractFourier transform carbon‐13 NMR spectra of a series of 3‐(X‐phenyl)glutaric anhydrides [X: H (2),4‐F (3), 4‐Cl (4), 4‐Br (5), 4‐OCH3 (6), 4‐NO2 (7), 3‐Cl (8) and 2,6‐Cl2 (9)] and of 3‐methyl‐3‐(4‐chlorophenyl)‐ (10)‐, 3,3‐diphenyl‐ (11)‐ and 3,3‐(2,2′‐biphenylylene)‐glutaric anhydride (12) have been obtained and interpreted. Spectral assignments of the aromatic side‐chain carbons for 3–9 were made with the aid of additive parameters derived from suitably substituted toluenes for which unequivocal assignments are possible. The carbon‐13 and proton chemical shift data of the glutaric anhydride skeletal carbons and appended protons are compared and discussed in terms of conformational properties of the anhydride ring and its side‐chain. A set of substituent parameters (α: 17.6 ± 0.3 ppm, β: +7.0 ± 0.3 ppm and γ: −1.3 ± 0.3 ppm), which correlates the average effect of the XC6H4 nucleus on the chemical shifts of the glutaric anhydride ring carbon atoms in 2–8, has been generated.
Valence force fields for the difluoroethylenes
Authors: Oskam A. , Elst R. 
Published: September 2010

AbstractNormal coordinate calculations of cis‐ and trans‐CHFCHF and of CF2CH2 have been undertaken using Modified Valence Force Fields based on vibrational data of all the hydrogen and deuterium isotopes. A definite vibrational assignment is given for CF2CH2 based on new infrared and Raman gas phase spectra.The calculated valence force fields of cis‐ and trans‐difluoroethylene. vinylidene fluoride and the vinyl halides mutually agree very well.
The nuclear magnetic resonance spectra of diethyl Z‐ and E‐[2‐(methoxycarbonyl)vinyl]phosphonate
Authors: Meppelder F. H. , Beck H. C. 
Published: September 2010

AbstractThe 1H and 31P nmr spectra of the title compounds are reported. The geometrical isomers are assigned from their proton spectra in the vinylene region. A π‐interaction between the P atom and the CC bond is indicated by the difference in the geminal PH coupling constants of the two isomers and by the position of the 31P resonance.
Spectres et conformations, en solution, des complexes de transfert de charge entre les stilbènes para‐substitués et le tétracyanoéthylène
Authors: Albert J. L. , Gamier F. , Dubois J. E. 
Published: September 2010

AbstractSolutions of tétracyanoéthylène and nine mono‐ and di‐para‐substituted stilbene derivatives magnified image (XH, CH3, MeO, Cl, Br, NO2) show two charge transfer bands in the UV visible spectrum range, associated with two molecular complexes I and II. The position of the first band around 17000 cm−1 is highly dependent on the substituent, whereas the position of the second band is almost constant about 26000 cm−1 (except for the complex of 4,4′‐dimethoxystilbene).These two bands are assigned to the transitions from the two highest occupied molecular orbitals of the donors, calculated by the method of Huckel. Taking account of the symmetries of the stilbènes and tétracyanoéthylène molecular orbitals, two most probable configurations are proposed for these molecular complexes, I and II, and one in particular for the 4,4′‐dimethoxy derivative. The determination of the differences in formation enthalpy, ΔΔH, for these two complexes I and II, experimentally confirms the particular behaviour of the 4,4′‐dimethoxystilbene.
Studies on polypeptides XV Synthesis of L‐ and D‐homohistidine
Authors: Bloemhoff W. , Kerling K. E. T. 
Published: September 2010

AbstractOptical resolution of DL‐homohistidine could be effected by fractional crystallization of the diastereomeric hydrogen tartrates. Starting from L‐glutamic acid, the direct synthesis of L‐homohistidine was accomplished through a ten‐stage synthesis requiring the isolation of only six intermediates.
Proton NMR spectra of di‐iodobis(N,N‐di‐n‐butyldithiocarbamato)‐platinum
Authors: Willemse J. , Pijpers F. W. , Backus J. J. M. 
Published: September 2010

AbstractProton NMR spectra of cis‐Pt(Bu2dtc)2I2 show, between −100 and + 100°C, two triplets of the α‐protons, even at 220 MHz no further splitting of the triplets could be observed. At about 100°C both triplets coalesce to a single one due to an intramolecular process (ΔH≠ = 7.2 kcal/mole and ΔS≠ = −37 eu). The proton NMR spectrum of cis‐Pt(MeBzdtc)2I2 shows two signals for both the methyl and methylene protons; at about 100°C both doublets coalesce to singlets. The possible intramolecular processes were studied with a complete permutational analysis. The experimental data can be explained by assuming a slow exchange up to 100°C, then a fast racemisation process starts in which a heteropolar breaking of a Pt‐ligand bond is involved.The isomerization of trans‐ into cis‐Pt(Bu2dtc)2I2 was studied between −10° and + 35°C by proton NMR The activation parameters ΔH≠ = 17.2 kcal/mole and ΔS≠ = −17 eu suggest an ionic intermediate formed via rupture of a Pt‐I bond.
The direct synthesis of methylchlorosilanes: Kinetic measurements with a gas flow calorimeter
Authors: de Cooker M. G. R. T. , van Den Berg P. J. 
Published: September 2010

AbstractThe rate of the reaction of methyl chloride and silicon, copper functioning as a catalyst and zinc and aluminium as promoters, has been measured with a calorimeter. From the experimental results it follows that the calorimeter can be used to study the kinetics of the direct synthesis of methylchlorosilanes. At a temperature of 333°C and at pressures of 300–800 Torr the initial reaction rate can be described by the power function r = k Pn, with n, the order of the reaction with respect to methyl chloride, being equal to 0.94.
Determination of the optical purity and absolute configuration at the 2‐position of enzymatically prepared 2‐substituted prostaglandins
Authors: Bus J. , Korver O. 
Published: September 2010

AbstractCircular dichroism measurements and proton magnetic resonance measurements with chiral shift reagents were used to determine possible chirality at the 2‐position of 2‐substituted prostaglandins. Measurements were carried out on the prostaglandin E1 (PGE1) molecules or 2‐substituted suberic acids obtained from them by an ozonisation procedure. The following conclusions may be drawn:‐ In the PGE1‐forming reaction the enzyme exhibits a slight preference for one of the antipodes of the starting material.‐ (2R)‐2‐methyl‐PGE1 and (2R)‐2‐phenyl‐PGE1 are preferentially formed.‐ 2‐cyano‐PGE1 was also considered, but fast racemization prevented conclusions about the enzyme specificity.