S. Shatzmiller, Ben-Zion Dolithzky, E. Bahar
Apr 12, 1991
Citations
0
Influential Citations
10
Citations
Journal
European Journal of Organic Chemistry
Abstract
The synthesis of optically pure chloromethyl (―)-menthyl ether (2b) and its use in the synthesis of di- (―)-menthyl acetal (―)-menthyl (+)-menthyl acetals are described. The diastereomeric mixed acetals 7a, b and 8a, b are easily obtainable from the nitrones 5 and 6, KCN and 2b. The mixtures of diastereomers are separated into the pure components 7a, 7b and 8a, 8b by simple silica gel column chromatography. Hydrolysis of these products (H 2 O 2 /Na 2 CO 3 , ultrasound) followed by N-O cleavage affords the heterocyclic α-methyl-α-amino amides 11a, 11b and 12a, 12b. These are subsequently hydrolyzed to give the corresponding α-methyl-α-amino acids with S and R configuration, respectively