Chirospecific synthesis of (1S,3R)-1-amino-3-(hydroxymethyl)cyclopentane, precursor for carbocyclic nucleoside synthesis. Dieckmann cyclization with an .alpha.-amino acid

Stereoselective synthesis of γ-amino acids

“…Finally, hydrolysis of 948 gave (1R,3S)-CACP 14 (Scheme 239). 356 Oxidative degradation of 949 readily obtained from (+)-camphoric acid, 357 On the other hand, Joullié et al 364 have described the stereoselective synthesis of (1S,2S,3S)-3-amino-2-hydroxycyclohexanecarboxylic acid 1008, a cyclohexyl GABOB analogue. Initially, basic hydrolysis of 1002a and 1002b, obtained from a Diels-Alder reaction and from the aldol-metathesis approach, respectively, afforded the corresponding carboxylic acid 1003 in 98% yield, which by an iodolactonization reaction with iodonium biscollidine perchlorate gave iodolactone 1004 in 70% yield.…”

Syntheses of optically active 2-amino-4-oxobutyric acid and N,O-protected derivatives

“…In this case too, the nature of amino protection seems to be critical (Kokotos et al, 1998). (Weygand and Fritz, 1965) (a) (Faust et al, 1983) (a) (d) (Svete et al, 1994) (a) (David and Veyribres, 1970) (a) (Bold et al, 1990) (a) (Hoffmann and Zeiss, 1992) (Winkler and Burger, 1996) (a) (Burger et al, 1995) ( ) (a) (Ornstein et al, 1994) (Wernic et al, 1989) (a) (Bergmeier, 1993) (a) (Robl et al, 1995) (a) Synthesis of the aldehyde 1 is described in the experimental section. (b) Yield unknown, aldehyde 1 is unstable and is used as crude in the next step.…”

Enantiomerically Pure Dibenzyl Esters of l-Aspartic and l-Glutamic Acid

“…12 Last but not least, the enantiomers of dibenzyl aspartate (S)-1 and (R)-1 are useful C4 chiral building blocks as exemplified by the synthesis (a) of both the enantiomers of N-silylated benzyl 4-azetidinone-2-carboxylate, used to construct hydroxamic acid containing bicyclic β-lactams (I), 13 tricyclic diproline analogues (II), 14 trans-2-carboxyazetidine-3-acetic acids (III), 15 2-(3-pyridyloxymethyl)-azetidines (IV); 16 (b) of both the enantiomers of trans-2-(diphenylmethylethylideneamino)cyclopropanecarboxylic acid (V) to be incorporated in dipeptides; 17 (c) of a (2S,4R)-4-hydroxyornithine derivative (VI); 18 and (d) of (S)-2-aminoadipic acid δ-methyl ester (VII) (Chart 2). 19 The large employment of (S)-1 and (R)-1 as synthetic intermediates requires a simple, efficient, and robust method to obtain the diester directly from the amino acid enantiomers. The reaction of L-aspartic acid with excessive benzyl alcohol in the presence of little more than 1 equiv of p-toleuenesulfonic acid to give the p-toluenesulfonate of (S)-1 [(S)-1·TsOH] in high yield has long been known and appreciated for its straightforwardness; to our knowledge, the first reports date back to the 1950s.…”