S-Valerolactone

Cyclopentanone gives S-valerolactone, bp 98-100°/5 mm. The lactone may be converted as above to its S-hydroxyhydrazide and recrystallized from ethyl acetate, mp 105-106°. 

Node and Fuji have developed a new chiral synthesis of various alkaloids using chiral nitroalkene, (S)-(-)-2-methyl-2-(2 -nitrovinyl)-S-valerolactone. Scheme 8.11 shows a total synthesis of (-)-physostigmine, a principal alkaloid of the Calabar bean.53 The key nitroalkene is prepared by asymmetric nitroolefination of a-methyl-8-lactone using a chiral enamine (see... 

N-Methyb/>-toluenesulfonamide, 34, 97 /3-Methyl-S-valerolactone, 35, 87 Methyl vinyl ether, 34, 29 Methyl vinyl ketone, 37, 19 Michael condensation between 3-nitropro-pane and methyl acrylate, 32, 86 Monochlorourea, 30, 24, 25, 26 Monoethanolamine, 32, 19 Monoethyl malonate, 37, 34 Mucobromic acid, 32, 95... 

These trivial names are permitted -y-butyrolactone, y-valerolactone, and S-valerolactone. Names based on heterocycles may be used for all lactones. Thus, -y-butyrolactone is also tetrahydro-2-furanone or dihydro-2(3//)-furanone. 

Figure 3. Log-log plots of molar cycli-zation constant (K.J against ring size (x) for S-valerolactone (O) and t-caprolac-tone (9). The slopes of the straight lines are —2.5 (8).

Imidate salts having a syn conformation were also studied (33). Imidate salt 128 which has a syn conformation due to its cyclic structure, gave on basic hydrolysis a mixture of amidoalcohol 129 (66%), s-valerolactone (130, 33%) and dimethyl amine (33%). Likewise, the hydrolysis of imidate salt 131 gave a one to one mixture of the corresponding amidoalcohol 132 and y-butyro-lactone 133 plus dimethyl amine. 

Dialkyl-S-vaJerolaetones.1 Reaction of primary, tertiary-1,4-diols (1) with formic acid and 97-100% sulfuric acid (Koch-Haaf carboxylation2) provides 2,2-dialkyl-S-valerolactones (2) in high yield. 

For example, in the 13C NMR spectrum of S-valerolactone (Figure 13-47), the CH2 groups in the upper (off-resonance-decoupled) spectrum are split into triplets, but they appear as singlets in the lower (broadband-decoupled) spectrum. 

Vinyl ethers also react readily with sulphonyl azides to give imino-esters. For example, from dihydropyran and j -toluenesulphonyl azide, the arylsulphonylimine of S-valerolactone (290) was obtained in quantitative yield... 

ZrPA = Zirconium phosphate amorphous, TiPA = Titanium phosphate amorphous, SnPC = Tin phosphate crystaiiine, ZrWP = Zirconium/tungsto. phosphate, MeCN = Acetonitrile, AcOH = Acetic acid, CX = Cyclohexanone, CP = Cyclopentanone, PIN = Pinacolone, AP = Acetophenone, 6-HCA = 6-Hydroxycaproic acid, e-Cap. = e-Caprolactone, Polymer = Polycaprolactone of unknown molecular weight, DVL = S-Valerolactone, t-BA = t-Butylacetate, PhA = Phenyl acetate, PhOH = Phenol,... 

Kullmer, K., Kikuchi, H., Uyama, H., and Kobayashi, S. (1998) Lipase-catalyzed ring-opening polymerization of a-methyl-S-valerolactone... 

Grieco et al. have used this fragmentation to convert a cyclohexanone ring into a S-valerolactone ring as formulated (18) (22). 

More recently, Lopez-Luna et al. [54] reported the successful enzyme-mediated syntheses of polyester structures in SCCO2 and R-134a. Lipase-mediated synthesis of relatively high molecular weight poly(S-valerolactone) (PVL) was reported in SCCO2 and liquid R-134a solvent media. However, they found that polymers and copolymers... 

Off-resonance-decoupled and broadband-decoupled spectra of S-valerolactone, molecular formula C5H8O2. 

Stereoselective rearrangement of guaianolides bearing a double bond at the C(6)/C(6a) position occurs to give tricyclic S-valerolactones (Scheme 44). ... 

Lactone 6-(Hydroxymethyl) tetrahydro-2H-pyran-2-one, 9CI. 5-(Hydroxymethyl)-S-valerolactone [160226-44-8]... 

Hydroxymethyltetrahydropyran. Tetrahy-dro-2-(hydroxymethyl)pyran. 5-Hydroxy-methyl-S-valerolactone [100-72-1]... 

Soum and co-workers reported on experimental conditions such that La(0-i-C3H7)3 is a dimer or a trimer or a mixture of both, in equilibrium with nonassociated species. The number of active isopropoxy per La however depends on the monomer and the [monomer]o/[initiator]o molar ratio (58). Propagating poly(S-valerolactone) chains are aggregated in contrast to the poly(e-caprolactone) active ones. 

Table 20. Effect of Methyl Substituents on the Equilibrium and Rate Constants for the Formation of S-Valerolactone at 25°C...

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