Copper(I)-BINOL Catalyzed Domino Synthesis of 1,4-Benzoxathiines through 𝐂_{(𝐚𝐫𝐲𝐥)}-O Bond Formation

Table 2

Cu salt, solvent, base screening for domino synthesis of 1,4-benzoxathiine moiety^a.

Entry	Cu salt	Solvent	Base	Cu : L5 (mol %)	Yield (%)^b
1	CuI	CH3CN	Cs2CO3	20 : 20	62
2	CuBr	CH3CN	Cs2CO3	20 : 20	41
3	CuCl	CH3CN	Cs2CO3	20 : 20	39
4	CuCl2	CH3CN	Cs2CO3	20 : 20	47
5	Cu(OAc)2	CH3CN	Cs2CO3	20 : 20	35
6	Cu(OTf)2	CH3CN	Cs2CO3	20 : 20	37
7	Cu2O	CH3CN	Cs2CO3	20 : 20	08
8	CuI	DMF	Cs2CO3	20 : 20	15
9	CuI	DMSO	Cs2CO3	20 : 20	—
10	CuI	Dioxane	Cs2CO3	20 : 20	07
11	CuI	Toluene	Cs2CO3	20 : 20	12
12	CuI	CH3CN	K2CO3	20 : 20	44
13	CuI	CH3CN	K3PO4	20 : 20	45
14	CuI	CH3CN	Cs2CO3	10 : 10	35
15	CuI	CH3CN	Cs2CO3	20 : 10	31
16	—	CH3CN	Cs2CO3	— : 20	—
17	CuI	CH3CN	Cs2CO3	20 : —	—
18	—	CH3CN	Cs2CO3	— : —	—
19	CuI	CH3CN	—	20 : 20	—

^aReactions were carried out in pressure tube; ^bisolated yield.