Remote C(sp<sup>3</sup>)–H Oxygenation of Protonated Aliphatic Amines with Potassium Persulfate
作者:Melissa Lee、Melanie S. Sanford
DOI:10.1021/acs.orglett.6b03731
日期:2017.2.3
the development of a method for selective remoteC(sp3)–H oxygenation of protonated aliphatic amines using aqueous potassium persulfate. Protonation serves to deactivate the proximal C(sp3)–H bonds of the amine substrates and also renders the amines soluble in the aqueous medium. These reactions proceed under relatively mild conditions (within 2 h at 80 °C with amine as limiting reagent) and do not
The stereoselective reduction of ethyl 2-(benzamidomethyl)-3-oxobutanoate 1 using yeasts was investigated among a restricted number (12) of yeasts. Kluyveromyces marxianus var. lactis CL69 diastereoselectively produced (2R,3S)-ethyl 2-(benzamidomethyl)-3-hydroxybutanoate 2. whereas Pichia glucozyma CBS 5766 gave (2S,3S)-2 as the major stereoisomer. The biotransformations were independently optimized for minimizing by-product formation and maximizing the diastereoselectivity. Under optimized conditions, K. marxianus var. lactis CL 69 gave the (2R,3S)-ethyl 2-(benzamidomethyl)-3-hydroxybutanoate 2 with ee > 99% and de = 98%, while P. glucozyma CBS 5766 allowed for the production of (2S,3S)-2 with ee > 99% and de = 86%. (c) 2009 Elsevier Ltd. All rights reserved.