Table 40.

Scope of the asymmetric Friedel-Crafts alkylation of aryl ethers with Cu(OTf)₂ and ligand A of Figure 37 under solvent-free and highly concentrated reaction conditions.

entry	substrate		temp(°C)	time (h)	product	yield (%)	ee (%)
1		R = H	0	10		90	90
2		R = Me	−20	30		80	90
3		R = Ph	−20	28		55	90
4		R′ = n-Bu	−20	40		88	92
5		R′ = Ph	0	72		62	92
6a		R′ = CH2-2-C6H4-Br	15	18		96	92
7		R′ = CH2-4-C6H4-Br	25	36		85	91
8		R′ = CH2-Ph	0	16		98	90
9		R′ = CH2-3-C6H4-Cl	0	28		78	93
10		R = H	−20	30		62	93
11		R = Me	−20	30		75	90
12		R = Ph	−20	48		70	93

^ahighly concentrated with CH₂Cl₂.