Crystal Structure of Tricarbonyl-[2,3-η:O-σ-(7,7-dimethoxy-5,6-dimethylidenebicyclo[2.2.1]hept-2-ene)]iron

The product of the reaction of [Fe(benzalacetone)(CO)₃] with 7,7-dimethoxy-5,6-dimethylidenebicyclo[2.2.1] hept-2-ene is tricarbonyl-[2,3-η:O-σ-(7,7-dimethoxy-5,6-dimethylidenebicyclo [2.2.1]hept-2-ene)]iron. Crystals are monoclinic, space group P2¹/c with a = 6.612(2), b = 11.610(4), c = 18.604(6) Å, and β = 95.91(2)°. The coordination at the metal atom is trigonal bipyramidal. The equatorial sites are occupied by 2 CO's and by the midpoint of the endocyclic double bond of the organic ligand. The axial sites are occupied by one CO group and the O-atom of one MeO group of the C(OMe)₂ bridge. It is an uncommon example of a d⁸ metal carbonyl complex bearing an O-bonded ligand.     

Ironcarbonyl Complexes of 5,6-Dimethylidene-7-oxabicyclo[2.2.1]hept-2-ene Derivatives. Synthesis of Substituted Tricarbonyl(ortho-quinodimethane)iron Complexes and 2-Indanones

The l-dimethoxymethyl-5,6-dimethyldene-7-oxabicyclo[2.2.1]hept-2-ene ( 9 ) has been prepared. On treatment with Fe₂(CO)₉, the endocyclic double bond C(2)?C(3) was coordinated first giving the corresponding exo-Fe(CO)₄ complex 10 . The latter reacted with Fe₂(CO)₉ and afforded cis-heptacarbonyl-μ-[1RS,2SR,3RS,4SR,5RS,6SR-2,3-η: C5,6,C-η-(1-(dimethoxymethyl)-5,6-dimethylidene-7-oxabicyclo[2.2.1]hept-2-ene)]diiron ( 11 ) as a major product. On heating, 11 underwent deoxygenation of the 7-oxabicyclo[2.2.1]heptene moiety yielding tricarbonyl[C,5,6,C-η-(1-(dimethoxymethyl)-5,6-dimethylidenecyclohexa-1,3-diene)]iron ( 13 ). In MeOH, a concurrent, regioselective methoxycarbonylation was observed giving tricarbonyl[C,3,4,C-η-(methyl 5-(dimethoxymethyl)-3,4-dimethylidenecyclohexa-1,5-diene-1-carboxylate)]iron ( 14 ). Oxidative removal of the Fe(CO)₃ moiety in 13 and 14 did not afford the expected ortho-quinodimethane derivatives but led to CO insertions giving 2,3-dihydro-2-oxo-1Hindene-4-carbaldehyde ( 20 ) and methyl 7-formyl-2-3-dihydro-2-oxo-lH-indene-5-carboxylate ( 21 ), respectively.     

Chemo- and Stereoselective Coordination of 5,6-Dimethylidene-7-oxabicyclo[2.2.1]hept-2-ene by d8- and d6-Metal Carbonyls. Diels-Alder reactivity of Dienes Perturbed by Remote Olefin Complexation

The endocyclic double bond C(2), C(3) in 5,6-dimethylidene-7-oxabicyclo[2.2.1]-hept-2-ene ( 1 ) can he coordinated selectively on its exo-face before complexation of the exocyclic s-cis-butadiene moiety. Irradiation of Ru₃(CO)₁₂ or Os₃(CO)₁₂ in the presence of 1 gave tetracarbonyl [(1R,2R, 3S,4S)-2,3-η-(5,6-dimethylidene-7-oxabicyclo[2.2.1]-hept-2-ene)]ruthenium ( 6 ) or -osmium ( 8 ). Similarly, irradiation of Cr(CO)₆ or W(CO)₆ in the presence of 1 gave pentacarbonyl[(1R, 2R, 3S,4S)-2,3-η-(5,6-dimethylidene-7-oxabicyclo[2.2.1]hept-2-ene)]chromium (10) or -tungsten (11) . Irradiation of complexes 6 and 11 in the presence of 1 led to further CO substitution giving bed-tricarbonyl-ae-bis[(1R,2R,3S,4S)-2,3-η-(5,6-dimethylidene-7-oxabicyclo[2.2.1]hept-2-ene)]ruthenium ( 7 ) and trans-tetracarbonyl[(1R,2R,3S,4S)-2,3-η-(5,6-dimethylidene-7-oxabicyclo-[2.2.1]hept-2-ene)]tungsten (12) , respectively. The diosmacyclobutane derivative cis-m?-[(1R,3R,3S,4S)-(5,6-dimethylidene-7-oxabicyclo[2.2.1]hepta-2,3-diyl)]bis(tetracarbonyl-osmium) (Os-Os) (9) wa also obtained. The Diels-Alder reactivity of the exocyclic s-cis-butadiene moiety in complexs 7 and 8 was found to be significantly higher than that of the free triene 1 .     

Enantioselective synthesis of (+)-5,6-exo-(isopropylidendioxy)-2-phenylsulfonyl-7-oxabicyclo[2.2.1]hept-2-ene

The title compound (+)-1 has been synthesized in four steps from furan and dienophile (+)-3 via an asymmetric Diels–Alder reaction.     

W(II)-catalyzed hydroarylation of bicyclo[2.2.1]hept-2-ene by simple arenes

The tungsten(II) carbonyl compound (CO)₄W(μ-Cl)₃W(SnCl₃)(CO)₃ has been found to be a very effective catalyst for the hydroarylation of bicyclo[2.2.1]hept-2-ene (norbornene) conducted in arene solution at room temperature. Norbornene adducts with benzene, toluene, para-xylene, and mesitylene have been isolated and their structures have been unambiguously established by means of ¹H and ¹³C NMR spectroscopy. On the basis of ¹H NMR monitoring of several catalytic reactions, a possible mechanism involving coordination of norbornene to the W(II) atom and its activation has been proposed.     

Syntheses and Crystal Structures of Two New Iron-sulfur Carbonyl Complexes: [Fe2(SC6H4Cl)2(CO)6]·0.5(Et2O) and [Fe3(SC6H4NH2)6(CO)6]·2(MeOH)

Two new iron-sulfur carbonyl complexes, [Fe2(SC6H4Cl)2(CO)6]·0.5(Et2O) 1 and [Fe3(SC6H4NH2)6(CO)6]·2(MeOH) 2, have been prepared and characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. Crystal data for 1: monoclinic, C2/c, a = 18.4439(8), b = 11.0999(5), c = 25.1830(10)(A), β = 97.0370(10)o, V = 5116.8(4)(A)3, Z = 8, C20H13Cl2Fe2O6.50S2, Mr = 604.02, Dc = 1.568 g/cm3, μ = 1.540 mm-1, F(000) = 2424, the final R = 0.0545 and wR = 0.1454 for 3443 observed reflections with I > 2σ(I); 2: monoclinic, P21/n, a = 12.350, b = 26.3050(11), c = 16.057(A),β = 97.891(3)°, V = 5166.9(2)(A)3, Z = 4, C44H44Fe3N6O8S6, Mr = 1144.76, Dc = 1.472 g/cm3, μ = 1.128 mm-1, F(000) = 2352, the final R = 0.0442 and wR = 0.1197 for 7978 observed reflections with I > 2σ(I). Complex 1 contains one iron dimer, in which two tricarbonyliron(I) fragments are bridged together by two 4-chlorophenylthiolate ligands, whereas complex 2 contains a linear tri-iron cluster, in which two terminal tricarbonyliron(II) fragments and the central Fe(II) atom are linked together by six 4-aminophenylthiolate bridging ligands.     

Synthesis and aminolysis of N-(bicyclo[2.2.1]hept-5-en-endo-2-ylmethyl)-N-(oxiran-2-ylmethyl)(7,7-dimethyl-2-oxobicyclo[2.2.1]heptan-1-yl)methanesulfonamide

A new N-(oxiran-2-ylmethyl) (glycidyl) derivative has been obtained by reaction of N-(bicyclo-[2.2.1]hept-5-en-endo-2-ylmethyl)(7,7-dimethyl-2-oxobicyclo[2.2.1]heptan-1-yl)methanesulfonamide with epichlorohydrin. Its epoxidation and aminolysis have been studied, and the regioselectivity of these transformations has been determined by IR and ¹H NMR spectroscopy and mass spectrometry.     

Synthesis of 4, 8-dihydroxy-3-methyl-5,6-benzo-2-oxabicyclo[2.2.2]oct-5-ene

The title compound having the same relative configurations as granaticin($\text{1}$) and U-58,431($\text{2}$) was prepared either by dehydrogenative cyclization of the precursor $\text{9a}$ or by pinacol cyclization of the dicarbonyl compound $\text{15}$.     

Reactivity of [Te6Fe8(CO)24]2− and Its Conversion to [Te4Fe5(CO)14]2−

Whereas reaction of [PhCH₂NMe₃]₂|Te₆Fe₈(CO)₂₄] (1) in refluxing CH₂CI₂ forms Fe₂(CO)₆(μ0-) TeCH₂Te), treatment of 1 with Ph₂SnCl ₂ or Mel gave the oxidation product Te₂Fe₃(CO)₉. Oxidation of 1 with [Cu(CH₃CN)₄]BF₄ afforded Te₂Fe₃(CO)₉ in good yield. Cluster 1 was converted to [PhCH₂NMe₃][Te₄Fe₅(CO)₁₄] (2) in MeOH/CH₂Cl₂ solution. Cluster 2 was structurally characterized by single-crystal X-ray diffraction and spectral methods. Complex 2 is composed of two Te₂Fe₂(CO)₆ fragments linked by one Fe(CO)₂ group. 2 crystallizes in the orthorhombic space group Pbcn with a = 13.351 (4) Å, b = 13.417 (4) Å, c = 26.077 (3) Å, V = 4671 (2) Å ₃, Z = 4.     

Spectroscopic, quantum chemical DFT/HF study and synthesis of [2.2.1] hept-2'-en-2'-amino-N-azatricyclo [3.2.1.0(2,4)] octane

The compound 4-N-bicyclo [2.2.1] hept-2'-en-2'-amino-N-azatricyclo [3.2.1.0(2,4)] octane (2) has been synthesized and characterized by elemental analysis, IR, UV-vis, mass and NMR. Density functional theory (DFT) and Hartree-Fock (HF) calculations have been carried out for the title compound by using the standard 6-31G* basis set. The calculated results show that the predicted geometry can well reproduce the structural parameters. Predicted vibrational frequencies have been assigned and compared with experimental IR spectra and they complement each other. The theoretical electronic absorption spectra have been calculated by using CIS, TD-DFT and ZINDO methods. The (13)C NMR and (1)H NMR of compound (2) have been calculated by means of Becke 3-Lee-Yang-Parr (B3LYP) density functional method with 6-31G* basis set. Comparison between the experimental and the theoretical results indicates that density functional B3LYP method is able to provide satisfactory results for predicting NMR properties. On the basis of vibrational analyses, the thermodynamic properties of the title compound at different temperatures have been calculated.     

[SnI8{Fe(CO)4}4]2+: Highly Coordinated Sn+III8 Subunit with Fragile Carbonyl Clips

[SnI₈{Fe(CO)₄}₄][Al₂Cl₇]₂ contains the [SnI₈{Fe(CO)₄}₄]²⁺ cation with an unprecedented highly coordinated, bicapped SnI₈ prism. Given the eightfold coordination with the most voluminous stable halide, it is all the more surprising that this SnI₈ arrangement is surrounded only by fragile Fe(CO)₄ groups in a clip‐like fashion. Inspite of a predominantly ionic bonding situation in [SnI₈{Fe(CO)₄}₄]²⁺, the I^????I^? distances are considerably shortened (down to 371 pm) and significantly less than the van der Waals distance (420 pm). The title compound is characterized by single‐crystal structure analysis, spectroscopic methods (EDXS, FTIR, Raman, UV/Vis, Mössbauer), thermogravimetry, and density functional theory methods.     

(5R,6R)-6-苯基-5-(苯磺酰基乙酰基)二环[2.2.1]-2-庚烯的合成及结构表征

报道了一种制备4-苯基-1-苯磺酰基-3-丁烯-2-酮的新合成方法. 4-苯基-3-丁烯-2-酮与溴化试剂Ph₃P^＋CH₂CH₂- COOHBr 作用, 得到1-溴-4-苯基-3-丁烯-2-酮, 不经分离直接与苯亚磺酸钠发生亲核取代反应, 得到4-苯基-1-苯磺酰基-3-丁烯-2-酮. 将此反应产物作为亲双烯体与环戊二烯在手性钛金属催化剂催化下进行不对称Diels-Alder反应, 得到了＞99% ee 的环加成产物(5R,6R)-6-苯基-5-(苯磺酰基乙酰基)二环[2.2.1]-2-庚烯. 用X衍射法对产物的晶体结构进行了测定, 讨论了反应机理, 通过元素分析, NMR, MS对产物的结构进行了表征.