Table 3.

Scope of different nitrones

Entry	Nitrone 3	X	5: Y/ee(%)a, b	2a: R/ee(%)b, c	s d selectivity
1	3a: R1 = Ph	0.55	5a: 42/96	45/97	36
2	3b: R1 = p-Tolyl	0.56	5b: 45/98	48/97	76
3	3c: R1 = p-MeOC6H4	0.55	5c: 37/96	42/99	31
4	3d: R1 = p-ClC6H4	0.55	5d: 41/97	41/97	21
5	3e: R1 = p-BrC6H4	0.55	5e: 40/97	50/92	79
6	3f: R1 = p-FC6H4	0.57	5f: 45/95	47/99	80
7	3g: R1 = m-MeOC6H4	0.55	5g: 46/95	49/90	42
8	3h: R1 = 2-naphthyl	0.56	5h: 42/97	48/98	91
9	3i: R1 = 2-furyl	0.56	5i: 48/98	44/99	41
10	3j: R1 = 2-thienyl	0.56	5j: 42/97	48/90	33
11	3k: R1 = i-Pr	0.57	5k: 42/93	40/77	7
12e	3l: R1 = Cy	0.56	5l: 36/90	45/79	11

^aY/ee: isolated yield and ee value of 5

^bEe determined by chiral HPLC analysis

^cR/ee: the recovery and ee value of 2a

^d s = ln[(1 − C)(1 − ee)]/ln[(1 − C)(1 + ee)]; C refers to the conversion of (±)−2a (1-(yield of recovered 2a))

^e13:1 dr