Table 1. Synthesis of 2-Arylidenindan-1,3-dione by the Reaction of Indan-1,3-dione with Benzaldehyde under Various Conditions in the Presence of 2-HEAF^a.

entry	2-HEAF (mmol)	solvent	temp. (°C)	time	yield (%)b
1	0.0		r.t.	72 h	25
2	0.0	EtOH	r.t.	24 h	25
3	0.0	EtOH	reflux	24 h	25
4	11.2		r.t.	1 min	80
5	5.6		r.t.	1 min	80
6	1.1		r.t.	1 min	85
7	0.1		r.t.	1 min	98

^aReaction conditions: benzaldehyde (0.25 mmol), indan-1,3-dione (0.25 mmol), and 2-HEAF.

^bYields refer to the pure isolated products.