1006728-95-5Relevant articles and documents
Organocatalytic route to enantioselective synthesis of ceramide trafficking inhibitor HPA-12
Lalwani, Komal G.,Sudalai, Arumugam
, p. 2445 - 2447 (2016)
A new organocatalytic approach to the synthesis of ceramide trafficking inhibitor HPA-12 has been described starting from phenacyl bromide. The strategy involves chiral CBS reduction of γ-ketoester and proline-catalyzed α-amination reaction of aldehyde fo
Chemoselectivity Control in the Asymmetric Hydrogenation of γ- and δ-Keto Esters into Hydroxy Esters or Diols
Arai, Noriyoshi,Namba, Takanori,Kawaguchi, Kei,Matsumoto, Yuki,Ohkuma, Takeshi
, p. 1386 - 1389 (2018)
The asymmetric hydrogenation of aromatic γ- and δ-keto esters into optically active hydroxy esters or diols under the catalysis of a novel DIPSkewphos/3-AMIQ–RuII complex was studied. Under the optimized conditions (8 atm H2, Ru complex/t-C4H9OK=1:3.5, 25 °C) the γ- and δ-hydroxy esters (including γ-lactones) were obtained quantitatively with 97–99 % ee. When the reaction was conducted under somewhat harsh conditions (20 atm H2, [t-C4H9OK]=50 mm, 40 °C), the 1,4- and 1,5-diols were obtained predominantly with 95–99 % ee. The reactivity of the ester group was notably dependent on the length of the carbon spacer between the two carbonyl moieties of the substrate. The reaction of β- and ?-keto esters selectively afforded the hydroxy esters regardless of the reaction conditions. This catalyst system was applied to the enantioselective and regioselective (for one of the two ester groups) hydrogenation of a γ-?-diketo diester into a trihydroxy ester.
Catalytic Redox Chain Ring Opening of Lactones with Quinones to Synthesize Quinone-Containing Carboxylic Acids
Xu, Xiao-Long,Li, Zhi
supporting information, p. 5078 - 5081 (2019/09/03)
Catalytic ring opening of five- to eight-membered lactones with quinones is achieved through a redox chain mechanism. With low loading of a simple metal triflate Lewis acid catalyst and a chain initiator, C-H bonds of many quinones were efficiently functionalized with carboxylic acid-containing side chains. This method also features 100% atom economy and wide substrate scope. A novel route to the anti-asthma drug Seratrodast was developed. Mechanism study suggests that the redox chain reaction likely undergoes a carbocation intermediate.
Biotransformation of aromatic ketones and ketoesters with the non-conventional yeast Pichia glucozyma
Contente, Martina Letizia,Molinari, Francesco,Zambelli, Paolo,De Vitis, Valerio,Gandolfi, Raffaella,Pinto, Andrea,Romano, Diego
, p. 7051 - 7053 (2015/02/02)
The non-conventional yeast Pichia glucozyma CBS 5766 has been used for the biotransformation of different aromatic ketones and ketoesters. The growth and biotransformation conditions were optimised for the reduction of acetophenone and under optimised conditions, propiophenone, butyrophenone and valerophenone were reduced to the corresponding (S)-alcohols with high yields and enantioselectivity. Ketoreductase(s) of Pichia glucozyma showed high catalytic activities also towards aromatic β- and γ-ketoesters, being often competitive with esterase(s). These concurrent activities allowed for the preparation of hydroxyesters, hydroxyacids and lactones often in a very selective manner.
Asymmetric synthesis of di- and trisubstituted cyclopropanes through an intramolecular ring closure
Kallemeyn, Jeffrey M.,Mulhern, Mathew M.,Ku, Yi-Yin
supporting information; experimental part, p. 535 - 538 (2011/05/04)
An asymmetric synthesis of di- and trisubstituted cyclopropanes proceeding through an intramolecular ring closure of activated chiral benzyl alcohols has been developed. The chiral alcohol intermediates are obtained from asymmetric reduction of readily av
Synthesis and conformational studies of γ-aminoxy peptides
Chen, Fei,Song, Ke-Sheng,Wu, Yun-Dong,Yang, Dan
, p. 743 - 755 (2008/09/20)
We have synthesized a series of γ-aminoxy acids, including unsubstituted and γ4-Ph-, γ4-alkyl-, and γ3,4-cyclohexyl-substituted systems. Coupling of these monomers to oligomers can be realized using EDCl/HOBt (or HOAt) as the coupling agent. γ-Aminoxy peptides can form 10-membered-ring intramolecular hydrogen bonds - so-called γ N-O turns - between adjacent residues, the extent of which is controlled by the nature of the side chain of each γ-aminoxy acid residue, increasing from the unsubstituted γ-aminoxy peptide to the γ4-alkyl aminoxy peptides to the γ4-phenyl- and γ3,4-cyclohexyl-substituted aminoxy peptides. The presence of two consecutive homochiral 10-membered-ring intramolecular hydrogen bonds leads to the formation of a novel helical structure. Theoretical studies on a series of model peptides rationalize very well the experimentally observed conformational features of these γ-aminoxy peptides.
