Table 1. Optimization of the Reaction Conditions^a.

entry	1a/2a	solvent	yield (%)
1	1.0/1.0	H2O	19
2	1.0/1.5	H2O	67
3	1.0/2.0	H2O	70
4	1.0/3.0	H2O	73
5	1.0/2.0	nBuOAc	12
6	1.0/2.0	DMF	22
7	1.0/2.0	toluene	N.R.
8	1.0/2.0	PhCl	trace
9b	1.0/2.0	H2O	32

^aReaction conditions: 1a (0.3 mmol), solvent (3 mL), 120 °C (oil bath), 24 h, under air.

^b9 h.