Ethyl 3-hydroxy-4-pentenoate

A. Ethyl 3-hydroxy-4-pentenoate. A dry, 2-L, two-necked, round-bottomed flask, capped with septa and equipped with a thermometer (Note 1), magnetic stirring bar, and an argon inlet is flushed with argon and charged with dry tetrahydrofuran (400 mL, Note 2) and diisopropylamine (30.8 mL, 220 mmol, Note 3). The solution Is cooled to -30°C and butyllithium (BuLi) (93.2 mL, 220 mmol, 2.36 M solution in hexanes, Note 4) is added. The reaction is stirred for 15 min and cooled to -76° to -78°C. Dry ethyl acetate (19.5 mL, 200 mmol, Note 5) is added dropwise so that the Internal reaction temperature remains below -66°C (addition time 10-15 min). When addition of the ethyl acetate is complete, the reaction Is stirred for 50 min at -70° to -78°C. A solutior of freshly distilled acrolein (13.4 mL, 200 mmol, Note 6) and 100 mL of dry... 

Ethyl 3-hydroxy-4-pentenoate 4-Pentenoic acid, 3-hydroxy-, ethyl ester (9) (38996-01-9)... 

The conditions of Jones oxidation are compatible with complex organic compounds containing functional groups such as esters, ketones, amides and alkenes. For example, ethyl 3-hydroxy-4-pentenoate (7.3) on oxidation with Jones reagent gave ethyl 3-oxo-4-pentenoate (Nazarov s reagent) (7.4). 

Pentenoate Ethyl 2.2-Difluoro-3-hydroxy-5-phcnyl- E10b2. 52 (F.duct)... 

BENZYL-L-GLYCER ALDEHYDE AND ETHYL (R,E)-4-0-BENZYL-4.5-DIHYDROXY-2-PENTENOATE (Propanal, 3-hydroxy-2-(phenylmethoxy)-, (R)- and 2-Pentenoic acid, 5-hydroxy-4-(phenylmethoxy)-, ethyl ester, [R-(E)]-)... 

In contrast, the latter. ryw-isomer, ethyl (TS,2R)-2-(1 -hydroxymethyl)-4-pentenoate. was recently prepared as the only product of a reduction with an enzyme fraction obtained from baker s yeast176. Introduction of a sulfur-containing functional group into the substrate increases stereocontrol in baker s yeast reduction of many ketonesI2e>. 2-Methylthio-3-keto esters are selectively reduced to the (3S)-3-hydroxy esters (Table 5)123,127. The 2-methylthio group is easily removed by 3-chloroperbenzoic acid oxidation to the corresponding sulfoxide followed by subsequent reduction with aluminum-mercury amalgam. Thus, these compounds can also be used for the preparation of optically pure 2-unsubstituted 3-hydroxy esters. 

The principal volatile products formed on pyrolytic decomposition of D-xylan, xylotriose, xylobiose, and methyl /S-D-xylopyranoside were 3-hydroxy-2-penteno-1,5-lactone and 2-furaldehyde. These products appear to be formed in independent reactions, the lactone being derived from non-reducing D-xylopyranosyl residues. Oxidation of ethyl 4,6-di-0-acetyl-2,3-dideoxy-a-D-eryt/iro-hex-2-eno-... 

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