Diyne mediated formal synthesis of (−)-A26771B

A formal asymmetric synthesis of (−)-A26771B (1) has been achieved where optically active glycidol and Noyori asymmetric hydrogenation are applied to introduce asymmetric centers. Commercially available 1,7-octadiyne, (R)-glycidol and acetaldehyde are used as the starting materials. The outlined synthetic strategy involves fewer number of synthetic steps, applying simple chemical transformations.</p

Synthesis and Structural Characterization of Ruthenium Carbonyl Cluster Complexes Containing Platinum with a Bulky N‑Heterocyclic Carbene Ligand

The reaction of Ru₃(CO)₁₂ with Pt­(IMes)₂ in benzene solvent at room temperature afforded the monoplatinum–triruthenium cluster complex Ru₃Pt­(IMes)₂(CO)₁₁, <b>1</b>, in 21% yield and the trigonal bipyramidal cluster complex Ru₃Pt₂(IMes)₂(CO)₁₂, <b>2</b>, in 26% yield. The reaction of Ru­(CO)₅ with Pt­(IMes)₂ in benzene solvent at 0 °C yielded two trinuclear cluster complexes, the monoplatinum–diruthenium Ru₂Pt­(IMes)­(CO)₉, <b>3</b>, and the monoruthenium–diplatinum cluster complex RuPt₂(IMes)₂(CO)₆, <b>4</b>. The reaction of <b>2</b> with hydrogen at 80 °C afforded the tetrahydrido–tetraruthenium complex Ru₄(IMes)­(CO)₁₁(μ-H)₄, <b>5</b>, and the dihydrido–diruthenium–diplatinum complex Ru₂Pt₂(IMes)₂(CO)₈(μ-H)₂, <b>6</b>. All six compounds were structurally characterized by single-crystal X-ray diffraction analyses

Titanocene(III) Chloride Mediated Radical Induced Allylation of Aldimines: Formal Synthesis of C-Linked 4′-Deoxy Aza-disaccharide

Titanocene(III) chloride (Cp2TiCl) mediated radical induced allylation of aldimines for the preparation of homoallyl amines is described. The radical was generated from the allyl bromide using Cp2TiCl as the radical source. Formal synthesis of C(4)–C(5′)-linked 4′-deoxy aza-disaccharide is demonstrated and a study toward the bicyclic skeleton of alkaloids was also accomplished. The radical initiator Cp2TiCl was prepared in situ from commercially available titanocene dichloride (Cp2TiCl2) and Zn dust in THF under argon

Titanocene(III) Chloride Mediated Radical Induced Allylation of Aldimines: Formal Synthesis of C-Linked 4′-Deoxy Aza-disaccharide

Titanocene(III) chloride (Cp2TiCl) mediated radical induced allylation of aldimines for the preparation of homoallyl amines is described. The radical was generated from the allyl bromide using Cp2TiCl as the radical source. Formal synthesis of C(4)–C(5′)-linked 4′-deoxy aza-disaccharide is demonstrated and a study toward the bicyclic skeleton of alkaloids was also accomplished. The radical initiator Cp2TiCl was prepared in situ from commercially available titanocene dichloride (Cp2TiCl2) and Zn dust in THF under argon

Synthesis and Structural Characterization of Bimetallic Iron−Nickel Carbido Cluster Complexes

In acetonitrile solvent, Fe5(CO)15(μ5-C), 1, reacts with Ni(COD)2 at room temperature to afford the iron−nickel complex Fe5Ni(NCMe)(CO)15(μ6-C), 3. The acetonitrile ligand in 3 can be replaced by CO and NH3 to yield Fe5Ni(CO)16(μ6-C), 4, and Fe5Ni(NH3)(CO)15(μ6-C), 6, respectively. When refluxed in acetonitrile solvent, compound 3 loses a vertex to form the square pyramidal Fe4Ni complex Fe4Ni(NCMe)2(CO)12(μ5-C), 7. Compound 7 readily converts to Fe4Ni(NCMe)(CO)13(μ5-C), 8, by losing one of its acetonitrile ligands. Addition of acetonitrile to 8 gives compound 7. When heated to 110 °C under an atmosphere of CO, both compounds 7 and 8 furnish the octahedral Fe4Ni2 complex Fe4Ni2(CO)15(μ6-C), 9. All six compounds were structurally characterized by single-crystal X-ray diffraction analyses

Bimetallic Octahedral Ruthenium–Nickel Carbido Cluster Complexes. Synthesis and Structural Characterization

The reaction of Ru₅­(CO)₁₅­(μ₅-C) with Ni­(COD)₂ in acetonitrile at 80 °C affords the bimetallic octahedral ruthenium–nickel cluster complex Ru₅Ni­(NCMe)­(CO)₁₅­(μ₆-C), <b>3</b>. The acetonitrile ligand in <b>3</b> can be replaced by CO and NH₃ to yield Ru₅Ni­(CO)₁₆­(μ₆-C), <b>4</b>, and Ru₅Ni­(NH₃)­(CO)₁₅­(μ₆-C), <b>5</b>, respectively. Photolysis of compound <b>3</b> in benzene and toluene solvent yielded the η⁶-coordinated benzene and toluene Ru₅Ni carbido cluster complexes Ru₅Ni­(CO)₁₃­(η⁶-C₆H₆)­(μ₆-C), <b>6</b>, and Ru₅Ni­(CO)₁₃­(η⁶-C₇H₈)­(μ₆-C), <b>7</b>, respectively. All five new compounds were structurally characterized by single-crystal X-ray diffraction analyses

Monitoring Photochemical Reaction Pathways of Tungsten Hexacarbonyl in Solution from Femtoseconds to Minutes

Metal–organic complexes are widely used across disciplines for energy and biological applications, however, their photophysical and photochemical reaction coordinates remain unclear in solution due to pertaining molecular motions on ultrafast time scales. In this study, we apply transient absorption and tunable femtosecond stimulated Raman spectroscopy (FSRS) to investigate the UV photolysis of tungsten hexacarbonyl and subsequent solvent binding events. On the macroscopic time scale with UV lamp irradiation, no equilibrated intermediate is observed from W­(CO)₆ to W­(CO)₅(solvent), corroborated by vibrational normal mode calculations. Upon 267 nm femtosecond laser irradiation, the excited-state absorption band within ∼400500 nm exhibits distinct dynamics in methanol, tetrahydrofuran, and acetonitrile on molecular time scales. In methanol, solvation of the nascent pentacarbonyl–solvent complex occurs in ∼8 ps and in tetrahydrofuran, 13 ps which potentially involves the associative oxygen-donating ligand rearrangement reaction. In contrast, a stimulated emission feature above 480 nm emerges after ∼1 ps in acetonitrile with a nitrogen-donating ligand. These structural dynamics insights demonstrate the combined resolving power of ultrafast electronic and stimulated Raman spectroscopy to elucidate photochemistry of functional organometallic complexes in solution. The delineated reaction pathways in relation to ligand nucleophilicity and solvent reorientation time provide the rational design principles for solution precursors in nanowrite applications