Whereas harnessing non-covalent interactions (NCIs) have largely been applied to late-transition metal complexes and to the corresponding catalytic reactions, there are very few examples showing the importance of NCIs in early-transition metal and main group metal catalysis. Here, we report on the effects of hydrogen bond donors in the catalytic pocket to explain the high activity and stereoselectivity of a series of aluminium catam complexes in rac-lactide ring-opening polymerisation (ROP). Four original aluminium catam catalysts have been synthetized and fully characterized. Structure-activity relationships and isotope effect show the importance of the NH moieties of the ligand in rac-lactide ROP. Computational studies highlight beneficial hydrogen bonds between the ligand and the monomer. Overall, structural characterization of the catalysts, mechanistic, kinetic and computational studies support the benefits of non-covalent interactions in the catalytic pocket.
A simple and highly efficient iron-catalyzed method for the chlorination of silanes has been developed. By use of 0.5−2% of the Fe(III)based catalyst FeCl 3 or Fe(acac) 3 in the presence of 1−1.5 equiv of acetyl chloride as the chlorine donor, a large number of silanes, alkoxysilanes, and silanols were converted to the corresponding chlorosilanes in 50−93% yields. In contrast to earlier reported methods often suffering from expensive catalysts or use of stoichiometric metal salts, hazardous reagents, and reaction conditions, the presently described methodology allows benign reaction conditions and simple workup while using only catalytic amounts of a readily available and economically viable iron catalyst.
Isoindolinone structure is an important privileged scaffold found in al argev ariety of naturallyo ccurring as well as synthetic, biologically and pharmaceutically active compounds. Owing to its crucial role in anumber of applications, the synthetic methodologies for accessingt his heterocyclic skeleton have received significant attentiond uring the past decade. In general, the synthetic strategies can be divided into two categories:F irst, direct utilization of phthalimides or phthalimidines as startingm aterials for the synthesis of isoindolinones;a nd second, construction of the lactam and/or aromatic rings by different catalytic methods, including CÀHa ctivation, cross-coupling,c arbonylation, condensation, addition and formal cycloaddition reactions. Especially in the last mentioned, utilization of transition metal catalysts provides access to ab road range of substituted isoindolinones.H erein, the recent advances (2010-2020) in transition metal catalyzed synthetic methodologies via formation of new CÀCbonds for isoindolinones are reviewed.
A simple iron-and silyl chloride catalyzed method for the preparation of symmetrical and nonsymmetrical ethers is presented. Various aldehydes and ketones were reductively etherified by using triethylsilane as a reducing agent in the presence of 2 mol% of iron(III) oxo acetate and 8 mol% of chloro(trimethyl)silane. The reactions can be carried out at ambient temperatures and pressures with ethyl acetate as the solvent.
A simple and efficient iron‐catalyzed method for arylation of aromatic carbonyl compounds is reported. The use of 4 % FeCl3 or Fe(acac)3 as the catalyst, in combination with a slight excess of chlorotrimethylsilane and triethylsilane, chlorination of benzylic ketones and aldehydes with subsequent Friedel–Crafts alkylation of arenes is achieved. Although the method is limited by the general constraints associated with Friedel–Crafts alkylation reactions, robust applications for the synthesis of pharmaceutical intermediates and so on can be envisioned.
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