Table 1: Optimization of the reaction condition and the catalyst recyclability with compound 4a.

EntryReaction conditionsTime (min)Yield (%)a

1KOH-alumina (5 mol%)357
2KOH-alumina (5 mol%)1064
3KOH-alumina (10 mol%)260
4KOH-alumina (10 mol%)472
5KOH-alumina (10 mol%)689
6KOH-alumina (10 mol%)888
7KOH-alumina (recycled once)1561
8KOH-alumina (recycled twice)1830
9KOH-alumina (recycled three times)2227

aIsolated yields.