Procedure:  2000 mL 1-neck flask, stirbar, Dean-Stark, condenser, septum, N₂ inlet

                  Dissolved 28.647 g of methyl levulinate (I) in 500 mL of benzene.  Stirred at rt and added 25.0 mL of ethylene glycol (II) followed by 0.569 g of p-TSA-H₂O.  Heated to reflux.  Water collected in the Dean-Stark trap and was periodically removed.  After 21 h, the reaction mixture was cooled to rt and washed with sat. aq. NaHCO₃.  The organic layer was dried over MgSO₄, filtered and the solvent was removed by rotary evaporation.  The product was isolated by short-path (fitted with a 3 in. vigreux) distillation (65 C, 0.25 mm) as a clear, colorless oil. 

 

¹H NMR (CDCl₃, 400 MHz) d 3.94 (m, OCH₂CH₂O), 3.67 (s, CO₂CH₃), 2.40 (t, J = 7.6 Hz, H2), 2.03 (t, J = 7.6 Hz, H3), 1.32 (s, H5). 

 

notes

 

This particular dioxalane ester was used in the synthesis of interemediates along the pathway to epibatidine (see Hernandez, A.; Marcos, M.; Rapoport, H.  J. Org. Chem.  1995, 60, 2683).