620594-25-4Relevant academic research and scientific papers
Direct synthesis of anthracenes from o-tolualdehydes and aryl iodides through Pd(II)-Catalyzed sp3 C–H arylation and electrophilic aromatic cyclization
Park, Hyojin,Yoo, Kwangho,Jung, Byunghyuck,Kim, Min
, p. 2048 - 2055 (2018/03/13)
The first direct synthesis of substituted anthracenes from o-tolualdehydes and aryl iodides via a Pd(II)-catalyzed C–H arylation using an alcohol-bearing transient directing group and subsequent AgOTf-assisted electrophilic aromatic cyclization is described. New transient directing groups consisting of amino acids and amino alcohols enhanced the reactivity, and the C–H arylation was complete in 12 h at 90 °C. By simply changing the silver salt to silver triflate, the one-pot synthesis of anthracene derivatives was carried out using the present reaction conditions.
Highly Enantioselective Iridium-Catalyzed Hydrogenation of Cyclic Enamides
Salomó, Ernest,Orgué, Sílvia,Riera, Antoni,Verdaguer, Xavier
supporting information, p. 7988 - 7992 (2016/09/13)
The MaxPHOX–Ir catalyst system provided the highest selectivity ever reported for the reduction of cyclic enamides derived from α- and β-tetralones. This result indicates that iridium catalysts are also proficient in reducing alkenes bearing metal-coordinating groups. In the present system, selectivity was pressure-dependent: In most cases, a decrease in the H2pressure to 3 bar resulted in an increase in enantioselectivity. Moreover, the process can be carried out in environmentally friendly solvents, such as methanol and ethyl acetate, with no loss of selectivity.
Employing the structural diversity of nature: Development of modular dipeptide-analogue ligands for ruthenium-catalyzed enantioselective transfer hydrogenation of ketones
Pastor, Isidro M.,Vaestilae, Patrik,Adolfsson, Hans
, p. 4031 - 4045 (2007/10/03)
A library of novel dipeptideanalogue ligands based on the combination of tert-butoxycarbonyl(N-Boc)-protected a-amino acids and chiral vicinal amino alcohols were prepared. These highly modular ligands were combined with [{RuCl2(p-cymene)}2 and the resulting metal complexes were screened as catalysts for the enantioselective reduction of acetophenone under transfer hydrogenation conditions using 2-propanol as the hydrogen donor. Excellent enantioselectivity of 1-phenylethanol (up to 98% ee) was achieved with several of the novel catalysts. Although most of the ligands contained two stereocenters, it was demonstrated that the absolute configuration of the product alcohol was determined by the configuration of the amino acid part of the ligand. Employing ligands based on L-amino acids generated S-configured products, and catalysts based on Damino acids favored the formation of the R-configured alcohol. The combination N-Boc-L-alanine and (R)-phenylglycinol (Boc-L-Ab) or its enantiomer (N-Boc-D-alanine and (S)-phenylglycinol, Boc-D-Aa) proved to be the best ligands for the reduction process. Transfer hydrogenation of a number of aryl alkyl ketones were evaluated and excellent enantioselectivity, up to 96 % ee, was obtained.
