------------------------------------ Reaction conditions and yields Compound Base Reaction Yield no. time (h) (%) 6 KOtBu 1.5 82 7 KOtBu 3 64 KOtBu 2 85 8 K2CO3 2 47 KOtBu 1.5 87 9 K2CO3 3 47 DBU 3 54 KOtBu 2 51 10 K2CO3 3 58 KOtBu 2 78 11 K2CO3 2 63 12 K2CO3 2 86 14 K2CO3 2 44 15 K2CO3 2 37 KOtBu 2 88 16 K2CO3 3 75 DBU 2 58 17 K2CO3 2 64 K2CO3 4 52 19 Cs2CO3 3 55