Table 2.

C7-debenzylation conditions of 5,6,7-trisubstituted 3-benzylidene-4-chromanone (18e).

Entry	Condition	Yield (%) a
		19	20
1	H2, Pd/C (3 mol %), MeOH, rt	65	-
2	TMSI b, CH2Cl2, rt	-	60
3	HBr (47%), 50 °C	-	60
4	TiCl4 (1 eq), CH2Cl2, 0 °C	NR c
5	Li, naphthalene, THF, −25 °C	NR

^a Isolated yield; ^b trimethylsilyl iodide; ^c no reaction.