Morpholin-2-one

The asymmetric synthesis of 2,3-diamino acids can be accomplished by the addition of chiral enolates to prochiral imines. For example, reaction of morpholine-2-one 103, derived from (S)-phenylglycinol, with N-benzyl ben-zaldimine in the presence of pyridine and para-toluenesulfonic acid at high... 

Moreover, Kim and coworkers have shown that a-amino-butyrolactones can be synthesized by a related process employing the amino acid homoserine with an unprotected hydroxy functionality [31]. In a more recent publication by the same research group, morpholin-2-one derivatives of type 9-37 have been prepared (Scheme 9.6) [32]. Herein, glycolaldehyde dimer 9-32 acts as a bifunctional compound, which first reacts with the a-amino acids 9-33 to give the iminium ions 9-34,... 

Substituted morpholin-2-one-5-carboxamide derivatives have been efficiently synthesized from commercially available glycolaldehyde dimer as the bifunctional component with various a-amino acids and isocyanides [80]. 

R,5R,6S)-4-tert-Butoxycarbonyl-5,6-diphenyl-3-(r-prop-2 -enyl)morpholin-2-one 4-Morpholinecarboxylic acid, 2-oxo-5,6-diphenyl-3-(2-propenyl)-, 1,1-dimethylethyl ester, 3R-... 

West, F. G., Naidu, B. N. Applications of Stevens [1,2]-Shifts of Cyclic Ammonium Ylides. A Route to Morpholin-2-ones. J. Org. Chem. 

Among the several examples given, the reaction of ( )-(55,67 )-4-rert-butoxycarbonyl-3-ethylidene-5,6-diphenyl-3,4,5,6-tetrahydro-2//-morpholin-2-one (20) with the ylide from racemic (diethylamino)(methyl)(oxo)(phenyl)sulfonium tetrafluoroborate to give the cyclopropane derivative 21 in 82% yield with 100% diastereofacial selectivitycan be mentioned. 

Oxobutanoic acid (5) has been converted to (/ )- or (S)-2-aminobutanoic acid via diastereo-controlled hydrogenation of the corresponding homochiral 3-ethyl-5-phenyl-3,4-dehydro-morpholin-2-one derivatives (6)139. 

The reaction of pentafluorobenzoylpyruvic acid (as well as the reaction of aroyl-pyruvic acid) with ethanolamine in dioxane yields 3-pentafluorobenzoylmethylene-morpholin-2-one. Due to the presence of ortho-fiuorine in the aromatic ring, the latter is capable of further cyclization forming 4-oxo-7,8,9,10-tetrafluoro-l,2,4, 5-tetrahydro[l,4]oxazino[4,3-<2]-4-quinolone (94JFC(69)119, 94IZV279) (Scheme 63). 

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