A Domino Copper-Catalyzed C-N and C-O Cross-Coupling for the Conversion of Primary Amides into Oxazoles
作者:Frank Glorius、Kerstin Schuh (née Müller)
DOI:10.1055/s-2007-983782
日期:2007.7
A variety of oxazoles can efficiently be prepared, in a single step and in good yield, from primaryamides and 1,2-dihaloalkenes using copper-catalysis. This new method allows the re-gioselective formation of a range of substituted oxazoles. The required 1,2-dihaloalkenes can prepared by simple treatment of alkynes with elemental bromine or iodine.
Oxidative functional group transformations with hydrogen peroxide catalyzed by a divanadium-substituted phosphotungstate
作者:Noritaka Mizuno、Keigo Kamata、Kazuya Yamaguchi
DOI:10.1016/j.cattod.2011.07.007
日期:2012.5
equivalent H+ to form a bis-μ-hydroxo species [γ-PW10O38V2(μ-OH)2]3− (I′) in organic media. The strong electrophilic oxidants such as [γ-PW10O38V2(μ-OH)(μ-OOH)]3− (II) and [γ-PW10O38V2(μ-η2:η2-O2)]3− (III) are formed by the reaction of the bis-μ-hydroxo species with H2O2. In the presence of I and H+, H2O2-based oxidations such as (i) epoxidation of alkenes (17 examples including electron-deficient ones),
甲二钒取代的磷钨TBA 4 [γ-PW 10 ö 38 V 2(μ-OH)(μ-O)](我,TBA =四Ñ -butylammonium)与一种当量H起反应+以形成双- μ -hydroxo物种[γ-PW 10 ö 38 V 2(μ-OH)2 ] 3-(我')在有机介质中。强电氧化剂如[γ-PW 10 ö 38 V 2(μ-OH)(μ-OOH)] 3-(II)和[γ-PW 10 ö 38 V 2(μ-η 2:η 2 -O 2)] 3-(III)是通过用H双- μ-羟物种的反应形成2 Ò 2。在I和H +的存在下,基于H 2 O 2的氧化,例如(i)烯烃的环氧化(17个实例,包括缺电子的烯烃),(ii)烷烃的羟基化(11个实例),以及(iii)氧化烯烃,炔烃,并与溴芳烃的溴化-作为溴源(包括氯化的12个例子),化学,非对映体和区域选择性地以中等至高收率,高效率地利用H 2 O 2来产生相应的氧化产物。
Synthesis and oxidation catalysis of a Ti-substituted phosphotungstate, and identification of the active oxygen species
report the synthesis of a Ti-substituted phosphotungstate, TBA6[(γ-PW10O36)2Ti4(μ-O)2(μ-OH)4] (I, TBA = tetra-n-butylammonium), and its application to H2O2-based oxidation. Firstly, an organic solvent-soluble dilacunary phosphotungstate precursor, TBA3[γ-PW10O34(H2O)2] (PW10), has been synthesized. By the reaction of PW10 and TiO(acac)2 (acac = acetylacetonate) in an organic medium (acetonitrile), I can
InCl<sub>3</sub>-Catalyzed Synthesis of 1,2-Dimetallic Compounds by Direct Insertion of Aluminum or Zinc Powder
作者:Tobias D. Blümke、Thomas Klatt、Konrad Koszinowski、Paul Knochel
DOI:10.1002/anie.201205169
日期:2012.9.24
In‐sertion of metal: Catalytic amounts of InCl3 allow the insertion of aluminum and zinc into aromatic 1,2‐dibromides or 1,2‐bromotriflates (see scheme). These 1,2‐dimetallic species can undergo Cu or Pd‐catalyzed acylations, allylations, or cross‐couplings.
Amino triphenolate tungsten(VI) complexes have been prepared and they proved to be efficient catalysts in haloperoxidation reactions using hydrogen peroxide as a terminal oxidant and inorganic sources of halides. In particular, interesting results have been obtained in the challenging chloroperoxidation reactivity (catalyst loading down to 0.05% with TONs up to 900). A comparison among three different