Table 6.

1,2-Halogen Migration/Cycloisomerization toward Halofurans 21

Entry	Substrate	Time	Product		Yield (%)a
1		1 day		21b	75
2		1 day		21c	73
3		1 hr		21d	73
4		1 day		21e	61
5		0.5 hr		21f	88
6		3 days		21g	73
7		5 min		21h	97
8b		1 hr		21i	71
9		3 days		21j	48
10b		1 hr		21k	67c
				21l

^aIsolated yields, reactions were performed on 0.29–1 mmol scale with 1 M concentration of 20.

^bMixture of allene and corresponding propargyl isomer was employed (see Supporting Information).

^cMixture (2:1) of 21k and 21l by ¹H NMR.