Table 3.

Substrate scope of the phosphane catalyzed coumarin synthesis.^a

Entry	Substrate	Product	Yield (%)b
1	1	2	82
2	3a	2	80
3	3b	4b	–c
4	3c	4c	96
5	3d	4d	88d
6	3e	4e	83
7	3f	4f	96
8	3g	4g	96
9	3h	4h	75
10	3i	4i	99

^aReactions were performed on a 1 mmol scale in 1 mL of methanol at 70 °C for 20 h. 15 min prior to workup, the mixture was quenched by addition of 1,2-dibromoethane (20 μL, 0.23 equiv). ^bYields of pure isolated material. ^cNo reaction to coumarin observed; starting material (60%) was reisolated. ^dReaction performed at 90 °C in a closed vessel.