Table 2.

¹H NMR spectroscopic monitoring of reaction of furan 1 with halobenzoylacetylenes in the Al₂O₃ medium.^a

Haloacetylene	Composition of the reaction mixture, %
	1 h				3 h				72 h
	1	3a	4a	5	1	3a	4a	5	1	3a	4a	5
	–	36	62	2	–	38	61	1	–	100	–	–
	–	44	56	–	–	49	51	–	–	88	12	–
	17	15	25	6	9	17	28	11	–	49	–	18

^b Content of iodobenzoylacetylene for 1 h, 3 h and 72 h was 37%, 35% and 33% correspondingly.

^aReaction conditions: 1 (1 mmol), halobenzoylacetylene (1 mmol), Al₂O₃ (ten-fold mass excess of the total mass of reagents), room temperature.