196107-42-3Relevant academic research and scientific papers
Stereoselective synthesis of cis- or trans-2,4-disubstituted butyrolactones from Wynberg lactone
Ganta, Ashok,Shamshina, Julia L.,Cafiero, Lauren R.,Snowden, Timothy S.
experimental part, p. 5396 - 5405 (2012/09/08)
(R)-Wynberg lactone was used to prepare various asymmetric 2,4-disubstituted butyrolactones in three to four steps. Attainment of any possible stereoisomer, based upon commencement from (R)- or (S)-4- trichloromethyl-2-oxetanone, and the capacity to insta
Catalytic asymmetric formation of δ-Lactones from Unsaturated acyl halides
Tiseni, Paolo S.,Peters, Rene
supporting information; experimental part, p. 2503 - 2517 (2010/09/03)
Previously unexplored enantiopure zwitterionic ammonium dienolates have been utilized in this work as reactive intermediates that act as diene components in hetero-Diels-Alder reactions (HDAs) with aldehydes to produce optically active δ-lactones, subunits of numerous bioactive products. The dienolates were generated in situ from E/Z mixtures of a,b- unsaturated acid chlorides by use of a nucleophilic quinidine derivative and Sn (OTf)2 as co-catalyst. The latter component was not directly involved in the cycloaddition step with aldehydes and simply facilitated the formation of the reactive dienolate species. The scope of the cycloaddition was considerably improved by use of a complex formed from Er- (OTf)3 and a simple commercially available norephedrine-derived ligand that tolerated a broad range of aromatic and heteroaromatic aldehydes for a cooperative bifunctional Lewis-acid-/ Lewis-base-catalyzed reaction, providing a,b-unsaturated d-lactones with excellent enantioselectivities. Mechanistic studies confirmed the formation of the dienolate intermediates for both catalytic systems. The active ErIII complex is most likely a monomeric species. Interestingly, all lanthanides can catalyze the title reaction, but the efficiency in terms of yield and enantioselectivity depends directly on the radius of the Ln III ion. Similarly, use of the pseudolanthanides ScIII and YIII also resulted in product formation, whereas the larger La III and other transition metal salts, as well as main group metal salts, proved to be inefficient. In addition, various synthetic transformations of 6- CCl3- or 4-silyl-substituted α,β-unsaturated d-lactones, giving access to a number of valuable δ-lactone building blocks, were investigated.
Practical asymmetric synthesis of β-trichloromethyl-β-hydroxy ketones by the reaction of chloral or chloral hydrate with chiral imines
Funabiki, Kazumasa,Honma, Norihiro,Hashimoto, Wataru,Matsui, Masaki
, p. 2059 - 2061 (2007/10/03)
(Matrix presented) Chloral or its hydrate undergoes the carbon-carbon bond-formation reaction with various optically active imines in the absence of any additive, followed by hydrolysis, to produce the corresponding β-trichloromethyl-β-hydroxy ketones in
