Synthesis of cyclopropane-fused spirooxindole^a.

Entry	R1	R2	R3	Yieldb (%) (6/9)	d.r.c
1	H	Ph	CH3	82/9	20 : 1 (6a)
2	H	2-FC6H4	CH3	74/10	18 : 1 (6b)
3	H	4-FC6H4	CH3	70/8	20 : 1 (6c)
4	H	3,4-Cl2C6H3	CH3	63/10	20 : 1 (6d)
5	H	4-BrC6H4	CH3	75/12	18 : 1 (6e)
6	H	2-CH3C6H4	CH3	80/9	20 : 1 (6f)
7	H	4-OCH3C6H4	CH3	81/7	20 : 1 (6g)
8	H	Thienyl	CH3	68/Trace	20 : 1 (6h)
9	H	Naphthyl	CH3	65/Trace	10 : 1 (6i)
10	H	OEt	CH3	79/8	20 : 1 (6j)
11	5-F	Ph	CH3	68/13	13 : 1 (6k)
12	7-F	Ph	CH3	70/10	20 : 1 (6l)
13	5-Cl	Ph	CH3	72/10	20 : 1 (6m)
14	6-Cl	Ph	CH3	79/12	20 : 1 (6n)
15	5-Br	Ph	CH3	80/5	15 : 1 (6o)
16	6-Br	Ph	CH3	81/8	9 : 1 (6p)
17	5-CH3	Ph	CH3	85/Trace	15 : 1 (6q)
18d	H	Ph	OEt	90/Trace	18 : 1 (6r)
19e	H	Ph	CH3	80/10	18 : 1 (6a)

^aUnless otherwise noted, all reactions were performed with 2 (0.15 mmol), 4 (0.165 mmol) in 2 mL DCM at 25 °C for 2 h.

^bIsolated yields of the major compound 6 and minor 9.

^cThe diastereoselective ratio of compounds 6 were calculated based on ¹H-NMR analysis of the crude reaction mixture.

^dThe relative configuration of 6r was determined by X-ray crystallographic analysis (Fig. 2), and the relative configurations of other products 6 were tentatively assigned by analogy.

^eA gram scale reaction of 2a (3.04 mmol) and 4a (3.34 mmol) in DCM at 25 °C was carried out.