Fig. 6: Control experiments.

a Use of 1,3-alkyne diols furnishing 6 M acyl carbonate 30. b Thermal stability check on seven-membered carbonate 3a. c Utilization of a different O-protecting group in the 5MCC precursor. d Attempted thermal activation of the pendant ketimine to force the domino synthesis of 17. e Attempted synthesis of a (5 + 5) bicyclic oxazolidinone from 31.