8-Valerolactone , ring opening

Bond JQ, Alonso DM, West RM, Dumesic JA (2010) y-Valerolactone ring-opening and decarboxylation over Si02/Al203 in the presence of water. Langmuir 26 16291-16298... 

Various cyclic esters have been subjected to hpase-catalyzed ring-opening polymerization. Lipase catalyzed the ring-opening polymerization of 4- to 17-membered non-substituted lactones.In 1993, it was first demonstrated that medium-size lactones, 8-valerolactone (8-VL, six-membered) and e-caprolactone (e-CL, seven-membered), were polymerized by lipases derived from Candida cylindracea, Burkholderia cepacia (lipase BC), Pseudomonas fluorescens (lipase PF), and porcine pancreas (PPL). °... 

Lipase catalyzed the ring-opening polymerization of medium-size lactones, d-valerolactone (<5-VL, six-membered) and -caprolactone (c-CL, seven-mem-bered). Lipases CC, PF and PPL showed high catalytic activity for the polymerization of <5-VL [74,75]. The molecular weight of the polymer obtained in bulk at 60 °C was relatively low (less than 2000). 

Ring-opening polymerization of a-methyl-substituted medium-size lactones, a-methyl-y-valerolactone and a-methyl-c-caprolactone, proceeded by using lipase CA catalyst in bulk [82]. As to (R)- and (S)-3-methyl-4-oxa-6-hexa-nolides (MOHELs), lipase PC induced the polymerization of both isomers. The apparent initial rate of the S-isomer was seven times larger than that of the R-isomer, indicating that the enantioselective polymerization of MOHEL took place through lipase catalysis [83]. 

The cationic ring opening polymerization of e-caprolactone, CL, and 8-valerolactone, VL, was investigated using n-Bu0H/HCl-Et20 as the initiation system [56]. It was observed that narrow molecular weight distribution samples were obtained. These results were combined with those previously... 

Kakuchi R, Tsuji Y, Chiba K, Fuchise K, Sakai R, Satoh T, Kakuchi T (2010) Controlled/ living ring-opening polymerization of 5-valerolactone using triflylimide as an efficient cationic organocatalyst. Macromolecules 43 7090-7094... 

Blanquer S, Tailhades J, Darcos V, Amblard M, Martinez J, Nottelet B, Coudane J (2010) Easy synthesis and ring-opening polymerization of 5-Z-Amino-8-valerolactone new degradable amino-functionalized (co)polyesters. J Polym Sci A Polym Chem 48 5891-5898... 

In the reactions of /1-propiolactone, y-valerolactone, and d-valerolactone no products could be isolated due to tarring,Lactides react with sulfur tetrafluoride, without ring opening, to give tetrafluorodioxanes and higher fluorinated dioxanes." 6-Chloro-4-hydroxycoumarin dimerizes upon reaction with sulfur tetrafluoride/hydrogen fluoride to a fluorinated spiro compound. - ... 

The treatment of 5-phenyl-5-(3 -bromopropyl)barbituric acid (145) with ammonium hydroxide yields 3-phenyl-3-allophanyl-2-piperidon. The reaction begins with the ammonolysis of 145 and then the resultant primary amino function attaches to the C-6 or C-4 carbonyl group of the ring with ring opening to yield 146, which then hydrolyzes to 147.400 5-Phenyl- and 5-allyl-5-(2 -hydroxypropyl)barbituric acids undergo similar intramolecular isomerization and a-phenyl-a-allophany,l-y-valerolactones are formed, respectively.359,401-403... 

Okumara et al. [10] were the first to attempt the enzyme-catalyzed synthesis of oligoesters from a reaction between dicarboxylic acids and diols. Gutman et al. [11] reported the first study on polyester synthesis by enzyme-catalyzed polymerization of A-B type monomers. Two independent groups in 1993 [12, 13] were first to report enzyme-catalyzed ring-opening polymerization (ROP). Their studies focused on 7- and 6-membered unsubstituted cyclic esters, e-caprolactone (e-CL) and 8-valerolactone (8-VL), respectively. 

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

Aluminum porphyrins initiate controlled ring-opening polymerizations of oxiranes [67-69] ]3-lactones [70-72], 5-valerolactone [74], -caprolactone [74] and D-lactide [75], as well as controlled addition polymerizations of methacrylates [76] and methacrylonitrile [77] (Eq. 15). As shown in Eq. (16), propagation occurs by a coordinative anionic mechanism... 

L.R. Rieth, D.R. Moore, E.B. Lobkovsky, G.W. Coates, Single-site P-diiminate zinc catalysts for the ring-opening polymerization of p-butyrolactone and p-valerolactone to poly (3-hydroxyalkanoales), J. Am. Chem. Soc. 124 (51) (2002) 15239-15248. 

The functional group compatibility of the click cyclization approach also makes it amenable to a variety of other polymerization techniques. For example, cyclic polyesters have been prepared using the Lewis acid-catalyzed ring-opening polymerizations (ROPs) of lactone monomers, including e-caprolactone [47, 48] and 5-valerolactone [49] from an azide-functionaUzed alcohol. Esterification of the terminal alcohol with pentynoic anhydride provided the complementary functional groups to enable an efficient click cycHzation for molecular weights up to 15 kDa. 

Kakuchi and coworkers reported controlled/living cationic ring-opening polymerizations of 8-valerolactone and s-caprolactone with the aid of diphenyl phosphate [89]. The reaction was illustrated as follows ... 

The ring-opening polymerization of 8-valerolactone and E-caprolactone was carried out using 3-phenyl-1-propanol as the initiator and diphenyl phosphate as the catalyst in toluene at room temperature. They reported that the reaction proceeded homogeneously to yield poly(8-valerolactone) and poly(s-caprolactone) with narrow polydispersity indices. Analyses indicated a presence of residues of the initiator. 

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