Table 2.

The scope of acceptors^a

En-try	Sub-strate	Acceptor	Temp (°C)	Time (h)	2	Yieldb	α:βc
1	α-1b	isopropanol	−30 → −20	50	2b	92%	1:7.5
2	β-1b		−40	48	2b	91%	9:1
3	α-1b		−40 → −30	48	2c	88%	1:4
4	β-1b		−40 → −30	36	2c	87%	23:1
5	α-1b	BnOH	−40 → −30	48	2d	93%	1:6.7
6	β-1b		−40	48	2d	95%	10:1
7	α-1b	t-BuOH	−40 → −30	48	2e	91%	1:6.5
8	β-1b		−30	36	2e	92%	6.7:1
9	α-1b		−40 → −30	48	2f	87%	1:11
10	β-1b		−30	36	2f	89%	10:1
11	α-1b	cholesterol	−20	36	2g	85%	1:8
12	β-1b		−30	36	2g	86%	8:1
13	α-1b		−20	36	2h	60%	1:2
14	β-1b		−30	36	2h	85%	2.2:1
15	β-1b		rt	8	2i	58%	1.6:1
16	β-1b		0	8	2j	83%	2:1

^aReactions were performed in sealed vials or Schlenk tube.

^bIsolate yields.

^cα:β ratio determined by crude ¹H NMR.