Optimization of reaction conditions^a.

S. no.	Catalyst (10 mol%)	Yieldsb (%)
1	PdCl2	25
2	Pd(PPh3)4	60
3	PdCl2(PPh3)2	30
4	Pd2(dba)3	39
5	Cu(OAc)2·2H2O	NR
6	Fe(acac)3	NR
7	CoCl2 anhyd.	Trace
8	NiCl2	NR
9	Ru(p-cym)Cl2 dimer	NR
10	(Cp*RhCl2)2	NR

^aReagents and conditions: a mixture of 3-phenyl-2H-benzo[b][1,4]oxazin-2-one (1a, 1 equiv.), NBS (2a, 1.2 equiv.), catalyst (10 mol%) and PTSA (0.5 equiv.) were irradiated with microwave under indicated solvent at indicated temperature for given period of time in sealed reaction vial.

^bIsolated yields.