13909-34-7Relevant articles and documents
The first enzyme-promoted addition of nitromethane to imines (aza-Henry reaction)
Janicki, Ignacy,?y?wa, Piotr,Kie?basiński, Piotr
, (2020)
Enzyme catalytic promiscuity is the ability of a single enzyme active site to catalyze several chemical transformations, among them those which are different from natural. We have attempted to use this feature of enzymes in the nucleophilic addition of nitromethane to aldimines (the aza-Henry reaction) whose chemically catalyzed version leads to synthetically useful β-nitroamines. We succeded in obtaining for the first time the desired products in the yields up to 81%. The most efficient proved lipase TL (from Pseudomonas stutzeri) and oxynitrilase from Arabidopsis thaliana. However, all the reactions investigated were non-stereoselective.
Synthesis of Enantiopure 6,11-Methylene Lipoxin B4 Methyl Ester
Trippe, Lukas,Nava, Analuisa,Frank, Andrea,Nubbemeyer, Udo
supporting information, p. 1156 - 1167 (2021/02/03)
The synthesis of Lipoxin B4 analogs (LXB4) to gain access to stabilized inflammation resolving compounds is an actual field of research. Focusing on variation and stabilization of the conjugated E,Z,E,E C6–C13 tetraene moiety of natural LXB4, a methylene bridge introduced between C6 and C11 suppresses any Z/E isomerization of the C8–C9 olefin. Intending to enable prospective structure variations in connection with the C1–C5 and C14–C20 fragments, a convergent total synthesis has been developed. Optically active C1–C12 building blocks were build-up from cycloheptatriene 1-carbonester (C6–C11, C21) and glutaryl chloride (C1–C5) using Friedel-Crafts-type acylation and chiral HPLC. The C13–C20 segment had been generated via a five-step sequence starting from heptanoyl chloride. Horner key olefination enabled the assembly of the carbon backbone. A final five-step sequence including a chelate Cram reduction of the unsaturated ketone moiety afforded the target 6,11-methylene LXB4 methyl ester.
Catalytic Asymmetric Hydroacyloxylation/Ring-Opening Reaction of Ynamides, Acids, and Aziridines
Li, Xiangqiang,Zeng, Hongkun,Lin, Lili,Feng, Xiaoming
supporting information, p. 2954 - 2958 (2021/05/05)
A highly enantioselective three-component reaction of ynamides with carboxylic acids and 2,2′-diester aziridines has been realized by using a chiral N,N′-dioxide/Ho(OTf)3 complex as a Lewis acid catalyst. The process includes the formation of an α-acyloxyenamide intermediate through the addition of carboxylic acids to ynamides and the following enantioselective nucleophilic addition to in-situ-generated azomethine ylides induced by the chiral catalyst. A range of amino acyloxyenamides are delivered in moderate to good yields with good ee values. In addition, a possible catalytic cycle with a transition model is proposed to elucidate the reaction mechanism.
