Synthesis of coumestans.

Entry	Substrate (3)	Coumestan (4)	% yielda
1	3aa		94
2	3ab		94
3	3ac		85
4	3ad		90
5	3ae		79
6	3af		78
7	3ag		96
8	3ah		89
9	3ai		89
10	3aj		91
11	3ba		93
12	3ca		75
13	3da		81
14	3ea		73

^aReaction conditions: [method C] a mixture of 3 (0.1 mmol), Pd/C (10 wt%) (3 mg, 0.3 mol%), NaOAc (1.5 equiv.) in 3 mL of DMA at 140 °C for 16 h.