Table 1. 1,4-Diastereoselectivity in the zirconocene-promoted allylic C–H bond activation and C–C bond cleavage.

Entry	R1	R2	R3	n	E1	E2	dr a	Yield b (%)
1	Pr	Bu	H	1(1b)	MeCOMe	H3O+	98 : 2	83 (3b)
2	Pr	Bu	H	1(1b)	[CH2]4CO	H3O+	98 : 2	62 (3c)
3	Pr	Bu	H	1(1b)	[CH2]5CO	H3O+	98 : 2	52 (3d)
4	Pr	Bu	H	1(1b)	EtCOEt	I2	98 : 2	56 (3e)
5	Pr	Bu	H	1(1b)	MeCOMe	I2	98 : 2	51 (3f)
6	Et	Bu	Me	2(1c)	MeCOMe	H3O+	98 : 2	62 (3g)
7	Et	Bu	H	3(1d)	MeCOMe	H3O+	98 : 2	61 (3h)
8	Et	Bu	H	3(1d)	[CH2]4CO	H3O+	97 : 3	61 (3i)
9	Et	Bu	H	3(1d)	[CH2]5CO	H3O+	98 : 2	62 (3j)
10	Et	Bu	H	3(1d)	MeCOMe	I2	96 : 4	55 (3k)
11	Et	Bu	H	3(1d)	EtCOEt	H3O+	98 : 2	59 (3l)
12	Et	Bu	H	4(1e)	MeCOMe	H3O+	98 : 2	50 (3m)

^aDetermined by ¹H NMR analysis of crude reaction mixture.

^bDetermined after purification by column chromatography on silica gel.