Electronic spectra and electrochemistry of disubstituted 2,2′-bipyridinetetracarbonylmolybdenum complexes. Solvent and substituent effects

Electronic absorption spectra of cis-[Mo(CO)₄(n,n′-X₂-bipy)] (n = 4, X = NMe₂, NH₂, OMe, CMe₃, Me, H, Ph, CH:CHPh, CO₂H, Cl, CO₂Me, NO; n=5, X = Me, CO₂H) have been measured at ambient temperature in a variety of solvents of different polarity. Emission spectra from glasses containing the complexes at 77 K have also been measured. The influence of the substituent X on the spectroscopic properties is correlated with the Hammett parameters, σ_p (X) and σ_p⁺ (X). The effect of solvent is correlated with the Taft-Kamlet parameter, π^★, indicating charge redistribution along the permanent dipole axis of the complex. The oxidation and reduction potentials in solution are simply related to the electronic effect of the substituent group, X, and are relatively independent of the solvent. The influence of the metal on these properties is not significant.     

17O NMR study of isomeric 2-R-2-oxo-1,3,2-dioxaphosphorinanes

Oxygen-17 NMR spectra were obtained from the four pairs of isomeric 2-R-2-oxo-1,3,2-dioxaphosphorinanes, where R=OMe (2), NMe₂ (3), H (4) or Me (5). The isomerism has been previously shown to be configurational at phosphorus, with one isomer of each pair having an equatorial phosphoryl oxygen (a isomer), and the other an axial orientation for phosphoryl oxygen (b isomer). Only data for the phosphoryl oxygen are reported. Substitution of OMe or NMe₂ for H or Me produced upfield shifts of 27.9-41.8 ppm. In all cases, the chemical shifts of the a isomers were upfield of the b analogs, with differences of 7.9, 18.0, 20.3 and 8.6 ppm for 2—5, respectively. The absolute values of ¹J(³¹P¹⁷O) were 5–9 Hz larger for the a isomers.     

Hydroformylation of 1-octene in the presence of cobalt alkylidynecarbonyl clusters

The hydroformylation of 1-octene in the presence of Co₃(CO)₉(-CR) (R=H, Me, Ph, CO₂Me, CO₂Et, CO₂Prⁱ, CO₂Bu^t, Cl, Br, OMe) alkylidynecarbonyl clusters, as well as triphenylphosphine derivatives of these complexes and heteronuclear Co₂Ni compounds have been studied. The nature of the catalytically active species in hydroformylation, as well as the processes of their formation and transformation during the reaction, have been established by means of IR spectroscopy. The effects of the reaction conditions, the nature of the substituent at the apical carbon atom, the electron donating phosphine substituent, and the substituent in the metal cluster framework have been discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1388–1393, August, 1993.     

Effects of substituents in the cationic and anionic η<Superscript>3</Superscript>-allylpalladium complexes according to data from <Superscript>13</Superscript>C NMR spectroscopy and quantum chemical calculations

A linear correlation of chemical shifts (δ) of signals in the ¹³C NMR spectra of the unsubstituted terminal carbon atom of the allyl ligand in [(1-R-η³-C₃H₄)Pd]NO₃ (R = Me, CH₂OMe, CO₂Me, COMe, CHO) with the substituent constants σ⁺ and σ^s- in acetone solutions was found. A considerable deviation from linearity was observed for R = Ph. The ¹³C nuclear magnetic screening constants were calculated by the DFT method in the GIAO approximation for equilibrium geometries of the cations [(1-R-η³-C₃H₄)Pd(Me₂C=0)₂]⁺ and anions [(1-R-η³-C₃H₄)PdCl₂]^s-. In the latter case, the theoretical and experimental δ values are consistent. The influence of the substituent R on the geometric parameters and charges on atoms in the neutral, anionic, and cationic η³-allylpalladium complexes is discussed.     

13C NMR of organosulphur compounds: I—the effects of sulphur substituents on the 13C chemical shifts of alkyl chains and of S-heterocycles

The ¹³C NMR spectra have been determined of: (i) aliphatic compounds having at one end a functionalized sulphur atom (? SH, ? S^?, ? SMe, ? S(O)Me, ? SO₂Me and ? S⁺Me₂) and (ii) saturated sulphur heterocycles variously substituted at the S-atom . The results are discussed in terms of the familiar deshielding effects for α- and β-carbons and shielding effects for γ-carbons, exerted by the sulphur atom itself and/or by the atoms or groups of which the sulphur function is made up. The γ-effect of the S-atom appears to be nearly independent of the nature of the S-function and of comparable magnitude to that of an aliphatic carbon (?2·5 + ?3·0 ppm). Surprisingly, however, a S? CH₃ group shields the carbon in γ position with respect to CH₃ by an amount (?5·4 ppm) which is more than twice that (?2·5 ppm) exerted by the aliphatic γ-carbon on the S-CH₃ carbon itself. As to the cyclic compounds, the shieldings of the α- and β-carbons can be rationalized in terms of the conformational orientation of the substituent at sulphur, and the equilibrium distribution of the conformers. The results confirm the great value of ¹³C NMR for configurational and conformational assignment of S-heterocycles.     

Metallkomplexe mit verbrückenden dimethylphosphidoliganden: VI. Zweikernkomplexe mit substituierten vinyldimethylphosphan-brückenliganden durch templatsynthese aus [(C5H5Co)2(μ-PMe2)2(μ-H)]+ und alkinen. Die kristallstruktur von [(C5H5Co)2(μ-PMe2)(μ-η4-Me2PC(CO2Me)CHC(OMe)O)]BF4

The hydrido-bridged dinuclear complex [(C₅H₅CO)₂(μ-PMe₂)₂(μ-H)]BF₄ (I) reacts with C₂(CO₂Me)₂ to produce a mixture of (C₅H₅Co)₂[μ-η⁴-Me₂PC(CO₂Me)C(CO₂Me)PMe₂] (II) and [(C₅H₅Co)₂(μ-PMe₂)(μ-η⁴-Me₂PC(CO₂Me)-CHC(OMe)O)]BF₄ (III). The X-ray structural analysis of III reveals that besides a dimethylphosphido bridge the cation contains a substituted vinyldimethylphosphine ligand which behaves as a 6-electron donor group and is coordinated via phosphorus and oxygen to the first cobalt and via the CC bond the second cobalt atom. The reactions of I with HC₂CO₂Me and CH₃C₂CO₂Me also give mixtures of products which contain the neutral component, (C₅H₅Co)₂[μ-η⁴-Me₂PCRC(CO₂Me)PMe₂] (IV: R  H; VII: R  CH₃), i.e., the structural analogue of II. The ionic products V, VI (obtained from HC₂CO₂Me) and VIII, IX (obtained from CH₃C₂CO₂Me) have been characterized by IR and NMR spectroscopy. {(C₅H₅Co)₂[μ-η⁴-PMe₂C(CH₃)C(CO₂Me)PMe₂](μ-H)}BF₄ (VIII) has independently been prepared by treatment of VII with HBF₄.     

Chemistry of Fischer-type rhenacyclobutadiene complexes. II. Reactions with alkynes and sulfonium ylides, and rearrangements induced by nitriles and pyridine

Further investigations into the chemistry of the rhenacyclobutadiene complexes (CO)₄Re(η²-C(R)C(CO₂Me)C(X)) (1: R=Me, X=OEt (1a), O(CH₂)₃CCH (1b), NEt₂ (1c); R=CHEt₂, X=OEt (1d); R=Ph, X=OEt (1e)) are reported. Reactions of 1 with alkynes at reflux temperature of toluene and at ambient temperature either under photochemical conditions or in the presence of PdO yield ring-substituted η⁵-cyclopentadienylrhenium tricarbonyl complexes, 2. The symmetrical alkynes R^′CCR^′ (R^′=Ph, Me, CO₂Me) afford the pentasubstituted complexes (η⁵-C₅(Me)(CO₂Me)(OEt)(Ph)(Ph))Re(CO)₃ (2d), (η⁵-C₅(Me)(CO₂Me)(OEt)(Me)(Me))Re(CO)₃ (2e), (η⁵-C₅(Me)(CO₂Me)(OEt)(CO₂Me)(CO₂Me))Re(CO)₃ (2f), and (η⁵-C₅(Me)(CO₂Me)(NEt₂)(CO₂Me)(CO₂Me))Re(CO)₃ (2i) on reaction with the appropriate 1, whereas the unsymmetrical alkynes R^′CCR″ (R^′=Ph; R″=H, Me) give either only one, (η⁵-C₅(Me)(CO₂Me)(OEt)(Ph)H)Re(CO)₃ (2a)), or both, (η⁵-C₅(Me)(CO₂Me) (OEt)(Ph)(Me))Re(CO)₃ (2b) and (η⁵-C₅(Me)(CO₂Me)(OEt)(Me)(Ph))Re(CO)₃ (2c), (η⁵-C₅(Ph)(CO₂Me)(OEt)(Ph)H)Re(CO)₃ (2g) and (η⁵-C₅(Ph)(CO₂Me)(OEt)(H)(Ph))Re(CO)₃ (2h), of the possible products of [3 + 2] cycloaddition of alkyne to η²-C(R)C(CO₂Me)C(X). Thermolysis of (CO)₄Re(η²-C(Me)C(CO₂Me)C(O(CH₂)₃CCH)) (1b) containing a pendant alkynyl group proceeds to (η⁵-C₅(Me)(CO₂Me)(O(CH₂)₃)H)Re(CO)₃ (2j), a η⁵-cyclopentadienyl-dihydropyran fused-ring product. Competition experiments showed that each of PhCCH and MeO₂CCCCO₂Me reacts faster than PhCCPh with 1a. The results with unsymmetrical alkynes are rationalized by steric properties of substituents at the CC and ReC bonds and by a preference of ReC(Me) over ReC(OEt) to undergo alkyne insertion. A mechanism is proposed that involves substitution of a trans CO by alkyne in 1, insertion of alkyne into ReC bond to give a rhenabenzene intermediate, and collapse of the latter to 2. Complexes 1a and 1d undergo rearrangement in MeCN at reflux temperature to give rhenafuran-like products, (CO)₄Re(κ²-OC(OMe)C(CHCR₂)C(OEt)) (R=H (3a) or Et (3b)). The reaction of 1d also proceeds in EtCN, PhCN, and t-BuCN at comparable temperature, but is slower (especially in t-BuCN) than in MeCN. In pyridine at reflux temperature, 1a undergoes a similar rearrangement, with CO substitution, to give (CO)₃(py)Re(κ²-OC(OMe)C(CHCEt₂)C(OEt)) (4). A mechanism is proposed for these reactions. The sulfonium ylides Me₂SCHC(O)Ph and Me₂SC(CN)₂ (Me₂SCRR^′) react with 1a in acetonitrile at reflux temperature by nucleophilic addition of the ylide to the ReC(Me) carbon, loss of Me₂S, and rearrangement to a rhenafuran-type structure to yield (CO)₄Re(κ²-OC(OMe)C(C(Me)CRR^′)C(OEt)) (R=H, R^′=C(O)Ph (5a); R=R^′CN (5b)). All new compounds were characterized by a combination of elemental analysis, mass spectrometry, and IR and NMR spectroscopy.     

1H, 13C and 29Si NMR study of α- and β-silylstyrenes and their adducts with dichlorocarbene

¹H, ¹³C and ²⁹Si NMR spectra for the α- and β-silylstyrenes (E)-PhCHCHSiR₃ (I) and PhC(SiR₃)CH₂ (II) (R = Cl, Me, Ph), and those for some dichlorocarbene adducts of I and II (R = Me, Ph), were examined. From the ¹³C NMR data, the phenyl substituent in the molecules I and II enhances the electronic effects of the organosilicon substituent at Cα, and weakens these effects on the C_α resonance. The degree to which polarization of the vinyl CC bond is polarized increases with increased electron-withdrawing properties of substituent R in the SiR₃ group in compounds I and II, and correlates with the reduced reactivity of the bond toward electrophilic dichlorocarbene. Several long-range coupling constants (CC) in the molecules I, II and in their adducts with :CCl₂ were measured. The estimated CC is a useful aid for the study of electronic effects in organosilicon compounds.     

Über bismut-haltige heterocyclen: I. Methylierte und phenylierte bismocane,intra- und intermolekulare koordinationserhöhung an bismut(III)

Methyl and phenyl oxadithia and trithiabismocanes have been synthesized from methyl or phenyl diethoxybismutane and the respective dithiol. The light-sensitive compounds have been investigated by mass, vibrational and ¹³C NMR spectra: ν(BiMe) 470–460, ν(BiS₂) 300–240 cm^?1; δ(¹³Me) ?12 ppm. The crystal structure of 5-phenyl-1,4,6,5-oxadithiabismocane has been determined (R = 0.056). The eight-membered ring has the chair-chair conformation. Besides three direct bonds (BiPh 225(2), BiS 256.0(2) and 260.2(3) pm) there are one transannular (Bi?O 297(1) and two intermolecular contacts (Bi ?S 344.0(3) and 350.9(3) pm) to bismuth in resulting a ψ-monocapped octahedral sphere of coordination. These polyhedra are connected in sharing two different edges, and the crystal structure exhibits double chains of molecules.     

Preparation and C NMR study on 1-aryl-3,3-difluoro-2-(phenylethynyl)cyclopropenes: long distance Hammett substituent effect

Coupling of 1-aryl-3,3-difluoro-2-chlorocyclopropenes and phenylacetylene using Sonogashira reaction with Pd(OAc)₂ and CuI as the catalyst with K₂CO₃ as a base yields phenylethynylcyclopropenes in high selectivity and good yields. The ¹³C chemical shifts of C? of ∼105 ppm on acetylene group significantly different from phenylacetylene (84 ppm) suggest that the acetylene group possesses less sp hybrid character due to an unusual long distance Hammett substituent effect. It is also confirmed by the substituent parameter analysis, while the Cβ and C? display the strong resonance effect (their values are 6.89 and 3.37, respectively).     

The 1H NMR spectra of methylmethoxyaluminium chloride and methylmethoxyaluminium iodide

It has been shown by means of ¹H NMR, IR and cryometrical measurements that, with oxygen bridges, Me(OMe)AlCl and Me(OMe)AII are trimers in solutions.Two isomers, cis and trans, are present, which are responsible for the multiple ¹H NMR spectra. The proton signals of MeAl and OMe groups are assigned in each isomer.     

Novel D- and T-functionalized Polysiloxane Matrices for Reactions in Interphases

New hydrocarbon bridged co-condensation agents of the type RSi(OMe)₂(CH₂)_zC₆H₄(CH₂)_z(OMe)₂SiR { 3[Ph(1,4-C₃D⁰)₂] , z = 3, R = Me; 3[Ph(1,4-C₃T⁰)₂] , z = 3, R = OMe; 4[Ph(1,4-C₃D⁰)₂] , z = 4, R = Me} were synthesized by hydrosilylation of the corresponding α,ω-dienes CH₂=CH–(CH₂)_z–2–C₆H₄–(CH₂)_z–2–CH=CH₂ [z = 3 ( 1 ), 4 ( 2 )] with HSiR(OMe)₂ (R = Me, OMe). These silane monomers were sol-gel processed, partially with MeSi(OMe)₃ ( T ⁰) to give the polysiloxanes 3 a , 3 b , 4 c , 3 d , 3 e , 4 f , and 3 ab (Table 1, Schemes 2 and 3); D = D type silicon atom (two oxygen neighbors), T = T type of silicon atom (three oxygen neighbors). The relative amounts of T and D silyl species and the degrees of condensation were determined by ²⁹Si and ¹³C CP/MAS NMR spectroscopic investigations. ²⁹Si and ¹³C CP/MAS NMR relaxation time studies (T_SiH, T_CH, T_1ρH), and 2 D WISE NMR experiments were applied to get knowledge about the polymer dynamics. For the first time protons of such polysiloxane systems were detected by ¹H SPE/MAS NMR measurements in suspension. Mobility studies were carried out in different solvents. Furthermore the swelling capacities of the polymers 3 a , 3 b , and 4 c in different solvents and the BET surface areas of all materials were investigated. SEM micrographs show the morphology of 3 a and 3 b .     

Structure and Photochemical Properties of r‐1, c‐2, t‐3, t‐4‐l, 3‐Bis [2‐ (5‐R‐benzoxazolyl) ] −2,4‐di (4‐R' ‐phenyl) cyclobutane

r‐1, c‐2, t‐3, t‐4‐1,3‐Bis[2‐(5‐R‐benzoxazolyl)]‐2,4‐di(4‐R'‐phenyl)cyclobutane (IIa: R=R' = H; IIb: R=Me, R'= H; IIc: R = Me, R' = OMe) was synthesized with high stereo‐selectivity by the photodimerization of trans‐l‐[2‐(5‐R‐benzoxazolyl)]‐2‐(4‐R'‐phenyl) ethene (Ia: R=R' = H; Ib: R = Me, R' = H; Ic: R = Me, R' = OMe) in sulfuric acid. The structures of IIa–IIc were identified by elemental analysis, IR, UV, ¹H NMR, ¹³C NMR and MS. The molecular and crystal structure of IIc has been determined by X‐ray diffraction method. The crystal of IIc (C₃₄H₃₀N₂O₄. 0.5C₂OH) is monoclinic, space group P2₁/n with cell dimensions of a = 1.5416(3), b =0.5625(1), c = 1.7875(4) nm, β = 91.56 (3)°, V= 1.550(1) nm³, Z = 2. The structure shows that the molecule of IIc is centrosymmetric, which indicates that the dimerization process is a head‐to‐tail fashion. The selectivity of the photodimerization of Ia–Ic has been enhanced by using acidic solvent and the reaction speed would be decreased when electron donating group was introduced in the 4‐position of the phenyl group. That the photodimerization is not affected by the presence of oxygen as well as its high stereo‐selectivity demonstrated that the reaction proceeded through an excited singlet state. It was also found that under irradiation of short wavelength UV, these dimers underwent photolysis completely to reproduce its trans‐monomers, and then the new formed species changed into their cis‐isomers through trans‐cis isomerization.     

Structural effects on the antitumour activity of a series of di(4-substituted phenyl)tin dichloride complexes with nitrogen-donor ligands

Investigation of the antitumour activity of a series of diorganotin dichloride complexes (4-ZC₆H₄)₂SnCl₂·L₂, where Z = OMe, Me, F, Cl, and CF₃ and L₂ = 2,2′-bipyridyl (bipy), 1,10-phenanthroline (phen) and 2-aminomethylpyridine (amp) is reported. A number of these complexex are shown to exhibit reproducible activity in vivo towards P388 lymphocytic leukaemia in mice. ¹H NMR data are reported for an extended series of (4-ZC₆H₄)₄Sn and the parent dichlorides (4-ZC₆H₄)₂SnCl₂ of the above-mentioned complexes. A correlation is reported between Hammett substituent constants and ¹H chemical shift data. Attempts are made to relate the antitumour activity of the complexes to various structural factors. The dependence of antitumour activity on the electronic effect of group Z and the nature of the ligand L₂ is demonstrated.     

Substituent effect on the diastereoselectivity in the chelation-controlled radical reactions of γ-(p-substituted-benzyloxy)-α-methylene esters with alkyl iodides

A pronounced substituent effect on the diastereoselectivity in the chelation controlled radical reactions of ethyl γ-(p-substituted-benzyloxy)-α-methylenecarboxylates with alkyl iodides was observed. The syn-selectivity increased in the order of electron-donating ability NO₂<CN<CF₃<F<H<i-Pr, Me, OMe of the p-substituent, and the plot of the log(syn/anti) versus Hammett sigma constants gave a linear correlation. The complexation experiments of the substrates with Lewis acid using ¹H NMR spectroscopy and the competition experiments between p-isopropylbenzyloxy and p-trifluoromethylbenzyloxy esters showed that the electron-donating p-isopropyl group stabilized the seven-membered chelate ring to give high syn-selectivity.     

NMR and stereochemical studies of non aromatic heterocyclic compounds—II : 13C and 31P NMR of 2-methoxy-1,3,2-dioxaphosphorinanes

¹³C and ³¹P chemical shift data for eight 2-methoxy-1,3,2-dioxaphosphorinanes are reported. Examination of pairs of geometrical isomers, which differ only in the orientation of the OMe substituent on P^III, have shown that both the ³¹P and the ¹³C signals of C_4,6 atoms appear 3–4 ppm at higher field when the OMe is axial compared with the equatorial isomer. This observation can be associated with the 1–3 syn diaxial interaction between the phosphorus axial substituent and the axial hydrogens on C_4,6 and should thus constitute, in the future, a supplementary tool for the structural analysis of this kind of compound. Important long range δ effects were observed both on ¹³C and especially on ³¹P chemical shifts. It is suggested that the high field δ_e effects could reflect a direct stereoelectronic interaction between the P atom and the cyclic C-5 atom. This interpretation is supported by a study of the ³¹P…¹³C coupling constants and their stereochemical dependence.     

Sulfur-containing carbene-metal compounds: General route from carbon disulfide manganese complexes; X-ray structure of 1,3-dithiol-2-ylidenemanganese(I) derivative

Chiral carbene-manganese(I) complexes have been synthesized by the cyclo-addition of dimethyl acetylenedicarboxylate to the coordinated CS₂ ligand in Mn(η²-CS₂)(CO)(L)C₅H₄R (L = P(OMe)₃; PMe₂Ph; PMe₃). Irrespective of the nature of the ligand L, these 1,3-dithiol-2-ylidenemanganese(I) complexes are stable towards isomerisation into heterometallocycles and exhibit low frequency carbonyl absorption bands in the infrared consistent with a strong electron releasing effect of the carbene ligand. The structure of Mn(CS₂C₂(CO₂Me)₂)(CO)(P(OMe)₃)(C₅H₅) has been determined by X-ray analysis of a suitable crystal. The molecule shows a carbene carbonmanganese bond C(7)Mn of length 1.876 Å and a planar carbene which does not adopt the 1,3-dithiolium aromatic-ring geometry but contains a carboncarbon double bond, C(8)C(9), of length of 1.341 Å. The CO₂Me groups are out of the plane of the carbene ligand and two positions with equal occupancy are found for each oxygen atom O(3) and O(5) belonging to the CO groups.     

Highly Efficient Transfer Hydrogenation Catalysis with Tailored Pyridylidene Amide Pincer Ruthenium Complexes

The rational optimization of homogeneous catalysts requires ligand platforms that are easily tailored to improve catalytic performance. Here, it is demonstrated that pyridylidene amides (PYAs) provide such a platform to custom-shape transfer hydrogenation catalysts with exceptional activity. Specifically, a series of meta-PYA pincer ligands with differently substituted PYA units has been synthezised and coordinated to ruthenium(II) centres to form bench-stable tris-acetonitrile complexes [Ru(R-PYA-pincer)(MeCN)₃](PF₆)₂ (R=OMe, Me, H, Cl, CF₃). Analytic studies including ¹H NMR spectroscopy, cyclic voltammetry, and X-ray crystallography reveal a direct influence of the substituents on the electronic properties of the ruthenium center. The complexes are active in the catalytic transfer hydrogenation of ketones, with activities directly encoded by the PYA substitution pattern. Their perfomance improves further upon exchange of an ancillary MeCN ligand with PPh₃. While complexes [Ru(R-PYA-pincer)(PPh₃)(MeCN)₂](PF₆)₂ were only isolated for R=H, Me, an in situ protocol was developed to generate these complexes in situ for R=OMe, Cl, CF₃ by using a 1:2 ratio of the complexes and PPh₃. This in situ protocol together with a short catalyst pre-activation provided highly active catalytic systems. The most active pre-catalyst featured the methoxy-substituted PYA ligand and reached turnover frenquencies of 210 000 h⁻¹ under an exceptionally low catalyst loading of 25 ppm for the benchmark substrate benzophenone, representing one of the most active transfer hydrogenation systems known to date.     

Electronic and Steric Structure of the Methanofullerene C61(CO2Me)[P(O)(OMe)2]. A Density Functional Study

The asymmetric addend in the methanofullerene C₆₁(CO₂Me)[P(O)(OMe)₂] polarizes and divides the fullerene shell into four nonequivalent fragments. According to DFT/PBE calculations, the most stable conformers of the methanofullerene C₆₁(CO₂Me)[P(O)(OMe)₂] involve Coulomb interactions of the phosphoryl oxygen with one of the fullerene carbon atoms, which produces polarization of the corresponding fragment and asymmetry in bond lengths and atomic charges in the fullerene shell. Alternation and attenuation of changes in bond lengths along the conjugation branches was revealed.     

Organometallische komplexverbindungen: VIII. Einfluss von achiralen substituenten auf die optische induktion bei der metallinduzierten synthese von 3-methyl-E-4-hexen-2-on

Bis(μ-methyl-1,3-dimethyl-η³-allylnickel) which has been modified by P ligands with a chiral substituent reacts with carbon monoxide under the formation of optically active 3-methyl-E-4-hexen-2-on. The investigated P ligands (PR^★R₂) have one chiral substituent (R^★ = 1R,3R,4S-(?)-menthyl) and the other substituents have been varied by taking the same alkyl or alkoxy groups (R = Me, Et, i-Pr, OMe, OEt, O-i-Pr). It has been found that the extent and the direction of optical induction depends on the concentration of the P-ligand and the kind of the achiral substituents at phosphorus.