A versatile access to unsymmetrical and symmetrical α-diketones via organotin reagents

Alkylation of osmium(VI) nitrido complexes: reaction of [Os(N)R4][NBu4] with [Me3O][BF4] and the x-ray crystal structures of [Os(N)(CH2SiMe3)4] [NBu4] and [Os(NMe)(CH2SiMe3)4]

“…NMR (THF-cZ8, -80 °C) 9 5.31, 5.25 (s, CgHiO, 3.83 (Ht), 2.44 (H2), 3.04 (H3), 2.17 (H4), 2.49 [Cr(7,5-C5H6)(7,6-C6Me6)], and binuclear, e.g., [|(0( 5-C5H5))2(^-C6Et6)], species which are presumably related to the j,5-pentamethylcyclopentadienyl chromium complexes reported by Wilke et al12 Details will be reported later. Reactions of unsaturated nitrogen ligands bound to transition metals are of interest as models for steps in the ammoxidation of olefins1 2and the reduction of dinitrogen.2 (1) Chang, A. O.; Oshima, K.; Sharpless, K. B. J. Am.…”

Access to carbon–carbon bonds

“…However, with transition metal catalysis, methoxymethyltin derivatives can also give cross-coupling products 454 (Scheme 10.84 When the a-heteroatom is doubly bonded to the carbon atom a similar situation arises. C-Phenyl C-stannyl imines react directly with acyl chlorides to afford a-diketones in moderate yield 445 , while acyltriorganotins necessitate palladium complex catalysis but offer a versatile route to unsymmetrical a-diketones 477 (Scheme 10.85 When symmetrical a-diketones are desired, the reaction of hexaalkylditins under similar experimental conditions appears to be a convenient route 477 ' 478 . However, to avoid decarbonylation, the reactions are better performed under carbon monoxide.…”

Palladium-Catalyzed Acetylation of Arenes

“… 13 , 14 For instance, Schmink and Krska employed arylsilylketones for the synthesis of biaryl ketones, 14 whereas others have studied the reaction of acyl silanes with allylic and benzylic substrates. 15 Herein, we demonstrate that acylsilane 3 readily undergoes Pd-catalyzed cross-coupling with a variety of aryl and hetaryl bromides to efficiently deliver aryl and hetaryl methyl ketones.…”

“…We envisioned an alternative approach that would employ commercially available acetyl­trimethyl­silane ( 3 ) . Acyl silanes, which are stable acyl anion precursors, exhibit umpolung reactivity of typical carbonyl moieties and have seen limited use in Pd-catalyzed cross-couplings. , For instance, Schmink and Krska employed arylsilyl­ketones for the synthesis of biaryl ketones, whereas others have studied the reaction of acyl silanes with allylic and benzylic substrates . Herein, we demonstrate that acylsilane 3 readily undergoes Pd-catalyzed cross-coupling with a variety of aryl and hetaryl bromides to efficiently deliver aryl and hetaryl methyl ketones.…”