Amines, 3-hydroxy asymmetric epoxidation

The [3-hydroxy amines are a class of compounds falling within the generic definition of Eq. 6A.6. When the alcohol is secondary, the possibility for kinetic resolution exists if the Ti-tartrate complex is capable of catalyzing the enantioselective oxidation of the amine to an amine oxide (or other oxidation product). The use of the standard asymmetric epoxidation complex (i.e., T2(tartrate)2) to achieve such an enantioselective oxidation was unsuccessful. However, modification of the complex so that the stoichiometry lies between Ti2 (tartrate) j and Ti2(tartrate)1 5 leads to very successful kinetic resolutions of [3-hydroxyamines. A representative example is shown in Eq. 6A.11 [141b,c]. The oxidation and kinetic resolution of more than 20 secondary [3-hydroxyamines [141,145a] provides an indication of the scope of the reaction and of some... 

Another class of reaction for which chiral tertiary amines are privileged catalysts is the Morita-Baylis-Hillman type (477, 478). One of the first applications of Cinchona alkaloids to mediate an asymmetric Morita-Baylis-Hillman reaction in a natural product synthesis was reported by Hatakeyama et al. in 2001 (479). Using a stoichiometric amount of (3-isocupreidine (568), a stereoselective addition of hexafluoroisopropyl acrylate (569) to aldehyde 570 could be carried out in good yield and with excellent selectivity (99% ee) (Scheme 119). The chiral p-hydroxy ester 571 was converted further into the epoxide 572, a known intermediate in the synthesis of epopromycin B (573). Epopromycin B (573) is a plant cell wall... 

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