1259290-91-9Relevant academic research and scientific papers
A Two-Component Alkyne Metathesis Catalyst System with an Improved Substrate Scope and Functional Group Tolerance: Development and Applications to Natural Product Synthesis
Schaubach, Sebastian,Gebauer, Konrad,Ungeheuer, Felix,Hoffmeister, Laura,Ilg, Marina K.,Wirtz, Conny,Fürstner, Alois
, p. 8494 - 8507 (2016/07/11)
Although molybdenum alkylidyne complexes such as 1 endowed with triarylsilanolate ligands are excellent catalysts for alkyne metathesis, they can encounter limitations when (multiple) protic sites are present in a given substrate and/or when forcing conditions are necessary. In such cases, a catalyst formed in situ upon mixing of the trisamidomolybenum alkylidyne complex 3 and the readily available trisilanol derivatives 8 or 11 shows significantly better performance. This two-component system worked well for a series of model compounds comprising primary, secondary or phenolic -OH groups, as well as for a set of challenging (bis)propargylic substrates. Its remarkable efficiency is also evident from applications to the total syntheses of manshurolide, a highly strained sesquiterpene lactone with kinase inhibitory activity, and the structurally demanding immunosuppressive cyclodiyne ivorenolide A; in either case, the standard catalyst 1 largely failed to effect the critical macrocyclization, whereas the two-component system was fully operative. A study directed toward the quinolizidine alkaloid lythrancepine I features yet another instructive example, in that a triyne substrate was metathesized with the help of 3/11 such that two of the triple bonds participated in ring closure, while the third one passed uncompromised. As a spin-off of this project, a much improved ruthenium catalyst for the redox isomerization of propargyl alcohols to the corresponding enones was developed.
Catalytic enantioselective arylation of glyoxylate with arylsilanes: Practical synthesis of optically active mandelic acid derivatives
Aikawa, Kohsuke,Hioki, Yueta,Mikami, Koichi
supporting information; experimental part, p. 2346 - 2350 (2011/06/26)
Just a little does the trick! The catalytic enantioselective arylation using chiral dicationic palladium complexes provides a reliable and useful access to enantiomerically enriched mandelic-acid derivatives. Significantly low catalyst loading (down to 0.002 mol%) as well as easy catalyst handling are the advantage of this practical method.
