The preparation of two new bisoxazolidines, two N-(2-hydroxyethyl)N-alkylglycine derivatives and two morpholones is described. The structure of (5S,6R)-N-isopropyl-5-methyl-6-phenyl-1,4-oxazin-2-one was established by Xray crystallographic analysis.
Nitriles under palladium-catalyzed hydrogenation conditions as substitutes for aldehydes in the reaction with 1,2-amino alcohols: Formation of 1,3-oxazolidines and reductive N-alkylation
hydrogen and catalytic amounts of Pd/C induced the formation of 1,3-oxazolidines fromnitriles and 1,2-aminoalcohols. The subsequent reductive cleavage of the NCO bond of these heterocycles occurred under the same conditions. Thus, this methodology provides a new one-pot N-alkylation of 1,2-aminoalcohols using nitriles as reagents with yields up to 98%.
作者:Jingjun Yin、Mark A. Huffman、Karen M. Conrad、Joseph D. Armstrong
DOI:10.1021/jo052121t
日期:2006.1.1
practical synthesis of ephedrine analogues in high yields and enantiopurity was realized by a highly diastereoselective Meerwein−Ponndorf−Verley (MPV) reduction of protected α-amino aromatic ketones using catalytic aluminum isopropoxide. The high anti selectivity resulted from the chelation of the nitrogen anion to the aluminum. In contrast, high syn selectivity was obtained with α-alkoxy ketones and other
Stereoselective synthesis of (1R)- and (1R,2S)-1-aryl-2-alkylamino alcohols from (R)-cyanohydrins
作者:Franz Effenberger、Beate Gutterer、Jürgen Jäger
DOI:10.1016/s0957-4166(96)00527-7
日期:1997.2
Hydrogenation of (R)-cyanohydrins (R)-1 with LiAlH4 occurs without racemization to give the (R)-2-amino alcohols (R)-3. (1R,2S)-2-Amino alcohols (1R,2S)-4 are obtained with high diastereoselectivity by addition of methyl Grignard to O-silyl protected cyanohydrins (R)-2 and subsequent hydrogenation with NaBH4. The N-alkylated 2-amino alcohols (R)-8 and (1R,2S)-9 can be prepared either by reductive alkylation