Table 1. Screening Reaction Conditions.

entry	catalyst	mol %	solvent	yield (%)
1	PdCl2	10	(CH2Cl)2	57a
2	PdCl2	10	CH2Cl2	92
3	PdCl2b	10	CH2Cl2	93
4	PdCl2	5	CH2Cl2	92
5	PdCl2	5	CH2Cl2	91c
6	PdCl2	2	CH2Cl2	45
7	PdCl2(CH3CN)2	5	CH2Cl2	82
8	Pd(OAc)2	10	CH2Cl2	0d
9	Pd/Ce		CH2Cl2	0d
10	Pd/Cf	5	CH2Cl2	0d
11	PdCl2(PPh3)2	10	CH2Cl2	0d
12	Pd2(dba)3	5	CH2Cl2	0d

^aReaction conducted at 50 °C; 3-ethyl-1H-isochromen-1-one (1c) was isolated.

^bPdCl₂ (99.999%).

^c1.0 mmol of 1a was used.

^dStarting material recovered.

^ePalladium (5%) on activated charcoal, 1 equiv.

^fPalladium (5%; 5 mol %) on activated charcoal and 5 mol % of LiCl.