posted July 28, 1999 12:32 PM            

You can react acetylene and formaldehyde; see Chem.Ing. Technik, 1950 p. 365.
Or Chem. Eng., v 58 p 176 (1951). It can also be prepared from ethylene
chlorohydrin, glutaric acid, hydroxybutyric acid solns, tetrahydrofuran or
vinylacetic acid. See Organic Chemisty (Van Nostrand, New York, 2nd ed. 1951).
The most recent reference I have can be found in the Journal of Organic
Chemistry v. 45 p. 1320 (1980).

I'll have to see if I can get those refs... There is not much on the internet about GBL because everbody still thinks it can be had easily.