Synthesis, Structure, and Reactions of Triaryl(methyl)bismuthonium Salts

Treatment of triarylbismuth difluorides 2 (Ar3BiF2; a, Ar = Ph; b, Ar = 4-MeC6H4; c, Ar = 4-MeOC6H4; d, Ar = 2-MeOC6H4) with methylboronic acid (3) in the presence of BF3·OEt2 in CH2Cl2 afforded the corresponding triaryl(methyl)bismuthonium tetrafluoroborates 4a−d ([Ar3MeBi+][BF4-]) in 42−91% yield. X-ray crystallographic analysis of compound 4d revealed that the bismuth center possesses a distorted tetrahedral geometry with C−Bi−C bond angles of 106.1(3)−113.6(3)° and Bi−C bond lengths of 2.182(7)−2.195(8) Å. Compound 4a transferred the methyl group to Ph3E (E = P, As, Sb), tris(4-methylphenyl)bismuthine, ROH (R = Me, Et, i-Pr, PhCH2), water, sodium benzenesulfinate, sodium benzoate, N,N-dimethylformamide (DMF), and thioacetamide to give the corresponding methylated products with a good recovery of triphenylbismuthine. The pseudo-first-order rate constant (kobsd = 2.9 × 10-4 s-1) observed for the reaction between 4a and benzyl alcohol (5d) was about twice as large as that (kobsd = 1.3 × 10-4 s-1) between MeOTf and 5d (in CDCl3 at 23 °C; [4a] or [MeOTf] = 0.062 M; [5d] = 0.97 M). The observed reactivity of 4a clearly demonstrates the high nucleofugality of the triphenylbismuthonio group

Synthesis, Structure, and Reactions of Triaryl(methyl)bismuthonium Salts

Treatment of triarylbismuth difluorides 2 (Ar3BiF2; a, Ar = Ph; b, Ar = 4-MeC6H4; c, Ar = 4-MeOC6H4; d, Ar = 2-MeOC6H4) with methylboronic acid (3) in the presence of BF3·OEt2 in CH2Cl2 afforded the corresponding triaryl(methyl)bismuthonium tetrafluoroborates 4a−d ([Ar3MeBi+][BF4-]) in 42−91% yield. X-ray crystallographic analysis of compound 4d revealed that the bismuth center possesses a distorted tetrahedral geometry with C−Bi−C bond angles of 106.1(3)−113.6(3)° and Bi−C bond lengths of 2.182(7)−2.195(8) Å. Compound 4a transferred the methyl group to Ph3E (E = P, As, Sb), tris(4-methylphenyl)bismuthine, ROH (R = Me, Et, i-Pr, PhCH2), water, sodium benzenesulfinate, sodium benzoate, N,N-dimethylformamide (DMF), and thioacetamide to give the corresponding methylated products with a good recovery of triphenylbismuthine. The pseudo-first-order rate constant (kobsd = 2.9 × 10-4 s-1) observed for the reaction between 4a and benzyl alcohol (5d) was about twice as large as that (kobsd = 1.3 × 10-4 s-1) between MeOTf and 5d (in CDCl3 at 23 °C; [4a] or [MeOTf] = 0.062 M; [5d] = 0.97 M). The observed reactivity of 4a clearly demonstrates the high nucleofugality of the triphenylbismuthonio group

Dimeric Triarylbismuthane Oxide: A Novel Efficient Oxidant for the Conversion of Alcohols to Carbonyl Compounds

Dimeric Triarylbismuthane Oxide:  A Novel Efficient Oxidant for the Conversion of Alcohols to Carbonyl Compound

A New, Efficient Method for Direct α-Alkenylation of β-Dicarbonyl Compounds and Phenols Using Alkenyltriarylbismuthonium Salts

Direct α-alkenylation of β-keto esters, β-diketone, and phenols with alkenyltriarylbismuthonium salts proceeded smoothly in the presence of 1,1,3,3-tetramethylguanidine to afford the corresponding α-alkenylated carbonyl compounds (β,γ-unsaturated carbonyl compounds) in good yields. The high leaving ability of the triarylbismuthonio group is a key driving force to achieve the C−C bond formation at the vinylic carbon under mild conditions

Dimeric Triarylbismuthane Oxide: A Novel Efficient Oxidant for the Conversion of Alcohols to Carbonyl Compounds

Dimeric Triarylbismuthane Oxide:  A Novel Efficient Oxidant for the Conversion of Alcohols to Carbonyl Compound

Synthesis and First X-ray Structural Analysis of Monomeric Imino-λ⁵-stibanes

Synthesis and First X-ray Structural Analysis of Monomeric Imino-λ5-stibane

Synthesis and First X-ray Structural Analysis of Monomeric Imino-λ⁵-stibanes

Synthesis and First X-ray Structural Analysis of Monomeric Imino-λ5-stibane

A New General Method for the Preparation of Unsymmetrical Telluronium Salts

A new general approach to a variety of unsymmetrical telluronium salts has been developed. Treatment of diaryltellurinyl difluorides 1 with silyl enol ethers 2 in the presence of BF3·OEt2 gave (2-oxoalkyl)diaryltelluronium tetrafluoroborates 3 in quantitative yield. When a siloxycyclopropane, an allylsilane, a benzylstannane, an alkenylstannane, an alkynylsilane, or an arylstannane was used in place of compound 2, the corresponding 3-oxoalkyl-, allyl-, benzyl-, alkenyl-, and alkynyldiaryltelluronium tetrafluoroborates as well as the unsymmetrically triarylated telluronium salt were obtained in good yields. The 125Te chemical shifts of these compounds span over the range δ 645−755 ppm, which were in accordance with the onium nature of the tellurium center. An X-ray structural analysis of 3a clearly showed that the central tellurium atom has a distorted-pyramidal structure with a weak coordinative interaction between the tellurium and carbonyl oxygen atoms. The telluronium salt [Ph2TeCH2CH2C(O)Bu-t]+[BF4]- easily transferred its alkyl moiety to a sulfinate anion to form the corresponding alkyl phenyl sulfone and diphenyl telluride, while the base-promoted reaction of [Ph2TeCH2C(O)Ph]+[BF4]- with benzaldehyde afforded a chalcone and diphenyl telluroxide

Synthesis, Structures, and Coordinating Properties of Phosphole-Containing Hybrid Calixpyrroles

Symmetric and asymmetric hybrid calixpyrroles containing a σ4-phosphole or σ4-2,3-dihydrophosphole unit (symmetric and asymmetric σ4-P,N2,X-hybrids: X = S, O) were prepared by using acid-promoted condensation reactions of the corresponding σ4-phosphatripyrranes with 2,5-bis(1-hydroxy-1-methylethyl)heteroles. The X-ray crystallographic analyses of the symmetric and asymmetric σ4-P,N2,X-hybrids show that the cavity sizes of the σ4-P,N2,S-hybrids are larger than those of the σ4-P,N2,O-hybrids, mainly reflecting the difference in edge-to-edge distances of the thiophene and furan rings. The symmetric σ4-P,N2,X-hybrids and the asymmetric σ4-P,N2,S-hybrid were successfully converted to the corresponding σ3 forms by reductive desulfurization at the phosphorus center. Each of the symmetric σ3-P,N2,X-hybrids was obtained as a mixture of two conformers, where the lone pair of the phosphorus atom is located inside (in) and outside (out) the cavity. The interconversion between the in and out type conformers of the asymmetric σ3-P,N2,S-hybrid was sufficiently slow to isolate each of them. The complexation reactions of the symmetric σ3-P,N2,S-hybrid with Au(I), Pt(II), and Pd(II) ions afforded both of the in and out type complexes, where the in type complexes were the thermodynamically favored products. In the complexation reactions of the asymmetric σ3-P,N2,S-hybrids, the stereochemistry at the phosphorus center was retained to give the in or out type complex exclusively. In the in-in type trans-M(II)-bis(phosphine) complexes (M = Pt, Pd) derived from the symmetric and asymmetric σ3-P,N2,S-hybrids, the M−Cl fragment is bound above the cavities of the two macrocycles. The crystal structures and the 1H NMR spectra of these M(II) complexes reveal that the P,N2,S-hybrid calixpyrroles bind the M−Cl fragments through P−M coordination and cooperative NH−Cl hydrogen-bonding interactions

Synthesis of α,α′-Linked Oligophospholes and Polyphospholes by Using Pd−CuI-Promoted Stille-Type Coupling

Palladium−copper-promoted Stille-type cross-coupling reactions between α-stannylphospholes and α-iodophospholes afforded α,α′-linked oligophospholes and polyphosphole efficiently. It has been revealed that the polyphosphole P-oxide possesses an extremely narrow band gap and a high electron-accepting ability as compared to polythiophene