- Zinc Acetate Catalyzed Enantioselective Reductive Aldol Reaction of Ketones
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A highly enantioselective method for the synthesis of β-hydroxy esters via reductive aldol reaction of acrylates with aryl and heteroaromatic ketones is described. In situ generated catalyst composed of zinc acetate and chiral diamine afforded enantioenri
- W?glarz, Izabela,Szewczyk, Marcin,Mlynarski, Jacek
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supporting information
p. 1532 - 1536
(2020/02/05)
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- Efficient syntheses of four stable-isotope labeled (1R)-menthyl (1S,2S)-(+)-2-phenylcyclopropanecarboxylates
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Many carbenoid cyclopropanation reactions promoted by chiral catalysts give product mixtures reflecting impressive diastereo- and enantioselectivities. Few provide a single chiral product efficiently. This limitation has been overcome in cyclopropanations of styrene and isotopically labeled styrenes with α-diazoacetates. Convenient syntheses on a 20 g scale of each of four chiral isotopically labeled (1R)-menthyl (1S,2S)-2- phenylcyclopropanecarboxylates (the 1-d-3-13C, 1,(3S)-d2, 1,2,(3S)-d3, and 1,3,3-d3 isotopomers) of better than 99% ee have been realized. The Royal Society of Chemistry 2006.
- Keliher, Edmund J.,Burrell, Richard C.,Chobanian, Harry R.,Conkrite, Karina L.,Shukla, Rajesh,Baldwin, John E.
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p. 2777 - 2784
(2008/09/16)
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- Organic chemistry: Preparative synthesis of the Corey chiral controller for enantioselective dihydroxylation of olefins
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A five-step synthesis of both enantiomers of 1,2-di(2,4,6-trimethylbenzylamino)-1,2-diphenylethane, i.e., Corey (R,R)- and (S,S)-controllers for enantioselective dihydroxylation of olefins by osmium tetroxide, starting from α,α'-diphenylglyoxime, has been developed. The key operations in the synthesis are the optical resolution of intermediate rac-1,2-diamino-1,2-diphenylethane into two enantiomers using only (R,R)-tartaric acid and the subsequent enhancement of the enantiomeric purity to >98% by crystallizations of the corresponding Schiff's bis-bases. Analysis of the enantiomeric purity of the controllers can be easily performed using 1H NMR spectra of their salts with (R)-α-methoxy-α-(trifluoromethyl)phenylacetic acid (Mosher R-acid).
- Lapitskaya,Pivnitsky
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