Synthesis of Polyfunctionalized 4H-Pyrans

Table 2

Optimization of catalyst loading.^a

Entry	Catalyst (mg)	Time (h)	Yield (%)
1	10	12	45^b
2	20	12	80
3	30	3	85
4	40	3	87
5	50	3	85

^aReaction conditions: stoichiometric ratio of all the reactants with base in ethanol at RT; ^bincomplete conversion.