Table 4. Allylic Oxidation of 12a#: Scope and Limitations.

entry	12	R1	R2	R3	Product	yield (%)
1	12aa	H	H	H	13aa	56
2	12ab	F	H	H	13ab	85
3	12ac	Cl	H	H	13ac	47
4	12ad	Br	H	H	13ad	43
5	12ae	I	H	H	13ae	29a
6	12af	OCH3	H	H	13af	78a
7	12ag	OH	H	H	13ag	<5b
8	12ah	CH3	H	H	13ah	n.d.c
9	12ai	CO2Et	H	H	13ai	36
10	12ak	CF3	H	H	13ak	22
11	12al	H	F	H	13al	33
12	12am	H	Cl	H	13am	60
13	12an	H	Br	H	14an	26
14	12ao	H	I	H	13ao	n.d.c
15	12ap	H	OCH3	H	13ap	24
16	12aq	H	CH3	H	13aq	37
17	12ar	H	CO2CH3	H	14ar	48
18	12at	H	H	OCH3	13at	56
19	12au	H	H	CO2CH3	14au	92

^aUnprotected phenols 14ae (16%) and 14af (ca. 10%) were isolated as byproducts.

^bDecomposition of starting material.

^cn.d.: not determined; oxidation products 13 were detected by NMR but could not be isolated in pure form due to inseparable byproducts.