Mechanochemical solid state synthesis of copper(I)/NHC complexes with K₃PO₄

• Ina Remy-Speckmann,
• Birte M. Zimmermann,
• Mahadeb Gorai,
• Martin Lerch and
• Johannes F. Teichert

Beilstein J. Org. Chem. 2023, 19, 440–447, doi:10.3762/bjoc.19.34

• ), 10 mol % 5, 1.1 equiv NaOt-Bu, 1.3 equiv 15-crown-5, 100 bar H2, 1,4-dioxane (3 mL), 70 °C, 24 h. Attempted direct synthesis of bifunctional catalyst 5 from imidazolinium salt 3: liquid and solid state approaches. Synthesis of standard Cu(I)/NHC-complexes using K3PO4 as a weak base (standard

New metathesis catalyst bearing chromanyl moieties at the N-heterocyclic carbene ligand

• Agnieszka Hryniewicka,
• Szymon Suchodolski,
• Agnieszka Wojtkielewicz,
• Jacek W. Morzycki and
• Stanisław Witkowski

Beilstein J. Org. Chem. 2015, 11, 2795–2804, doi:10.3762/bjoc.11.300

• may confer new properties of the NHC ligand. Results and Discussion Synthesis of the carbene precursor The synthesis of an imidazolinium salt as a carbene precursor was started from 2,2,5,7,8-pentamethylchromane (10), which was prepared by the reaction between 2,3,5-trimethylphenol and 3-methylbut-2

• of the nitro group in 11 was slightly troublesome, probably due to steric hindrance. The tellurium-rongalit system was found to be the most efficient [30], and 6-chromanylamine 12 was obtained in 50% yield. Imidazolinium salt 14 was prepared according to the classical protocol. Chromanylamine 12 was

• . Imidazolinium salt 14 was obtained by treatment of 13 with trimethyl orthoformate in 73% yield. It is worth noting that ethylenediamine 13 and imidazolinium salt 14 were sufficiently pure after precipitation, thus chromatographic purification was not necessary. Some specific effects are observed in the NMR

Efficient synthetic protocols for the preparation of common N-heterocyclic carbene precursors

• Morgan Hans,
• Jan Lorkowski,
• Albert Demonceau and
• Lionel Delaude

Beilstein J. Org. Chem. 2015, 11, 2318–2325, doi:10.3762/bjoc.11.252

• -methylphenyl)imidazolium chloride (IDip*·HCl or IPr*·HCl). Keywords: cyclization; experimental procedure; imidazolinium salt; imidazolium salt; microwave heating; Introduction Since Arduengo and co-workers successfully isolated and characterized the first imidazol-2-ylidene derivative in 1991 [1][2], stable

Imidazolinium and amidinium salts as Lewis acid organocatalysts

• Oksana Sereda,
• Nicole Clemens,
• Tatjana Heckel and
• René Wilhelm

Beilstein J. Org. Chem. 2012, 8, 1798–1803, doi:10.3762/bjoc.8.205

• TMSOTf gave the product in 55% yield. In both cases the endo product was the major product. The reaction was followed by TLC and the temperature was gradually increased from –10 to 45 °C over 4 days in ca. 10 °C steps. Next, imidazolinium salt 7 [25] was used in the reaction. The formation of the product

• , the bis-imidazolinium salt 10 [12] gave the product in 69% yield with an endo/exo ratio comparable to BF3•Et2O. The reaction started slowly at 10 °C. In addition, the similar salt 11 [12] gave the product in a comparable yield of 66%. Although in all cases the product was racemic, the results show

• -imidazolinium salt 10 was applied with thiirane 12 and aniline in CH2Cl2. A yield of 18% was obtained. However, in the absence of a solvent the yield increased to 98% after 16 h (Scheme 3). In the absence of a catalyst a yield of 12% was obtained under neat conditions. Product 13 was obtained in all reactions