Butyn Butyrolactone

As an application of maleate formation, the carbonylation of silylated 3-butyn-l-ol affords the 7-butyrolactone 539[482], Oxidative carbonylation is possible via mercuration of alkynes and subsequent Lransmetallation with Pd(II) under a CO atmosphere. For example, chloromercuration of propargyl alcohol and treatment with PdCF (1 equiv.) under 1 atm of CO in THF produced the /3-chlorobutenolide 540 in 96% yield[483]. Dimethyl phenylinale-ate is obtained by the reaction of phenylacetylene, CO, PdCU, and HgCl2 in MeOH[484,485]. 

In 1982, the ruthenium-catalyzed isomerization of 2-butyne-l,4-diol to butyrolactone was reported. This reaction was proposed to proceed through initial isomerization of 2-butyne-l,4-diol to a,/3-unsaturated aldehyde followed by cyclization and double bond isomerization (Scheme 52).91... 

DIHYDROFURAN DIVINYL ETHER METHACROLEIN 2-BUTYNE-1,4-DIOL ganna-BUTYROLACTONE cis-CROTONIC ACID trans-CROTONIC ACID METHACRYLIC ACID METHYL ACRYLATE VINYL ACETATE ACETIC ANHYDRIDE SUCCINIC ACID DIGLYCOLIC ACID MALIC ACID TARTARIC ACID n-BUTYRONITRILE ISOBUTYRONITRILE ACETONE CYANOHYDRIN... 

Isomerization of 2-butyne-1,4-diol. In the presence of this catalyst, 2-butyne-l,4-diol isomerizes to butyrolactone. RuH2[P(C6H5)3]3 is somewhat less active.2... 

Palladium(ll)-catalyzed intramolecular stereoselective Irons alkoxycarbonylation of 4-alkyl- and 4-aryl-3-butyn-l-ols 7 gives /f-tetrasubstituted a-methylene-y-butyrolactones 8 if conducted in the presence of copper(II) chloride, methyloxirane and triethyl orthoacetate. In the absence of the copper salt, intramolecular dicarbonylation occurs (e.g., giving 9, see Section 1.5.8.3.3.). The latter reaction type is also observed if the alkyne moiety is substituted by a trimethylsilyl instead of an alkyl or aryl group60,61. 

In the presence of CO, the Pd(PhCN)2Cl2-catalyzed cyclization of 1,1-disubstituted 4-(trimethylsilyl)-3-butyn-l-ols produces y-butyrolactones (eqs 73 and 74).4 ... 

Uses Corrosion inhibitor in acid pickles and cleaners pharmaceuticals intermediate electroplating brightener defoliant polymerization accelerator stabilizer for chlorinated hydrocarbons cosolvent for paint and varnish removal synthesis of histamine and pyridoxine alternative route for vitamin B6 Regulatory Canada DSL 2-Butyne-1,4-diol. See But-2-yne-1,4-diol Butyric acid lactone. See Butyrolactone Butyric alcohol. See Butyl alcohol Butyrolactam y-Butyrolactam. See 2-Pyrrolidone... 

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