Asymmetric reactions. XXVII. Absolute configurations of γ-butyrolactone-γ-carboxylic acid and γ-valerolactone-γ-carboxylic acid

Abstract

S)-y-Butyrolactone-y-carboxylic acid (III, R = H) (levorotatory in water, dextrorotatory in methanol), in form of its methyl ester III (R = CH 3 ), was reduced to (S)-( -)-1,2,5-pentanetriol (IV) the absolute configuration of which was determined by correlation with (R)-( + )-glycerraldehyde. The probable absolute configuration of (R)-y-valerolactone-y-carboxylic acid (VII, R = H) (dextrorotatory in ' water; levorotatory in methanol) has been derived by comparing ORD curves of the both acids studied, and their derivatives.

Synthesis of Heterocycles from Alkyl 3-(Dimethylamino)propenoates and Related Enaminones

“…Analogously to the ring switching synthesis of heteroarylalanines and heteroarylalaninols, 3-heteroaryl substituted lactic acid esters 202-204 can be prepared in one step from methyl (S)-3-[(E)-(dimethylamino)methylidene]-2-oxotetrahydrofuran-5-carboxylate (25a), available in two steps from (S)-2oxotetrahydrofuran-5-carboxylic acid. 57,167 32). 84,168 O-Benzoyl (S)-3-heteroarylpropane-1,2-diols 205-207 were prepared by ring switching methodology from (S)-5-benzoyloxymethyl-3-[(E)-(dimethylamino)methylidene]tetrahydrofuran-2-one (25b) upon acidcatalyzed treatment with 2-pyridineacetic acid de- rivatives, 1,3-dicarbonyl compounds and their analogues, and heteroarylhydrazines in 14-81% yields (Scheme 53; Table 33).…”

“…However, much less attention has been paid to the synthesis and utilization of heteroaryl substituted α-hydroxy acid derivatives. Analogously to the ring switching synthesis of heteroarylalanines and heteroarylalaninols, 3-heteroaryl substituted lactic acid esters 202 − 204 can be prepared in one step from methyl ( S )-3-[( E )-(dimethylamino)methylidene]-2-oxotetrahydrofuran-5-carboxylate ( 25a ), available in two steps from ( S )-2-oxotetrahydrofuran-5−carboxylic acid. , Lactone 25a affords, upon treatment with various ambident 1,3-dinucleophiles in refluxing acetic acid, the corresponding methyl ( S )-3-(4-oxo-4 H -quinolizin-3-yl)- ( 202a − c ), methyl 3-(2-oxo-2 H -pyran-3-yl)- ( 203a − j ), and methyl ( S )-3-(4-oxo-4 H -pyridino[1,2- a ]pyrimidin-3-yl)lactates ( 204a , b ) upon treatment with 2-(pyridin-2-yl)acetic acid derivatives, 1,3-dicarbonyl compounds and their analogues, and substituted 2-aminopyridines, respectively (Scheme ; Table ). ,

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Synthesis of the sex pheromone of the Japanese beetle

“…The stereospecificity (Brewster et al, 1950;Cervinka and Hub, 1968;Yamada et al, 1969) of the deamination (Austin and Howard, 1961;Plieninger et al, 1961;Ravid et al, 1978) ofR (V) or S glutamic acid has been known for some time, and the lactone acid product VI has been utilized as an intermediate in the synthesis of several natural products (Plieninger et al, 1961;Koga, 1971;Eguchi and Kakuta, 1974;Iwaki et al, 1974;Mori, 1975;Ravid et al, 1978). The stereospecific (Eguchi and Kakuta, 1974) conversion of VI to the acid chloride VII proceeded smoothly in high yield with either thionyl chloride or oxalyl chloride.…”

“…The R enantiomer of Ia [the Z isomer made from (R)-glutamic acid] was identical chemically and biologically to the natural pheromone, whereas the S enantiomer of Ia [prepared as in Scheme II, but starting with (S)-(+)-glutamic acid] was chemically, but not biologically identical to the natural pheromone. Since the absolute configuration of the (R)-tetrahydro-5-oxo-2-furancarboxylic acid has been determined (Cervinka and Hub, 1968;Ravid et al, 1978), the absolute configuration of the pheromone is established. One striking difference between the proton nuclear magnetic resonance ([1H]NMR) spectra of the Z and E isomers of either the R or S enantiomers of the pheromone was observed.…”

A convenient route to optically active γ-substituted γ-lactones

“…[8][9][10][11][12][13] The use of chiral reducing agents such as BINAP-Ru(II)-catalyzed hydrogenation, 14,15 hydrosilylation catalyzed by rhodium complexes with chiral phosphine ligands 16 and enzymatic hydrolysis of hydroxy esters 17 are some of the methods that have given satisfactory results. Optically pure g-substituted g-lactones have also been obtained from optically pure glutamic acid [18][19][20] with retention of configuration. However the use of an optically pure alcohol as a chiral auxiliary for the reduction of 4-oxobutanoates 1 using sodium borohydride, followed by hydrolysis, resulted in optically inactive g-lactones.…”