Table 1.

Preparation of Dienone Substrates 12 through Spirocyclization of Alkyl Hydroxamates 10.^a

entry	substrate	n	R1	R2	product	yield (%)b	drc
1	10a	0	Me	H	12a	53d	-
2	10a	0	Me	H	12a	67e	-
3	10b	0	Bn	H	12b	86e	-
4	10c	1	Me	H	12c	81	-
5	10d	1	Bn	H	12d	98	-
6	10e	2	Me	H	12e	92	-
7	10f	2	Bn	H	12f	83	-
8	10g	1	Me	Me	12g	85f	92:8
9	10h	1	Me	t-Bu	12h	82f	87:13
10	10i	1	Me	Bn	12i	98g	92:8
11	10j	1	Me	Ph	12j	85h	91:9
12	10k	1	Me	OTIPS	12k	99i	90:10
13	10l	1	Me	NHBz	12l	85f	91:9
14		-	-	-		90f	80:20
15		-	-	-		94	-

^aReaction conditions: PIFA (1.2 equiv), CH₂Cl₂-MeOH (1:1), −78→−15 °C, 1.5 h; H₂O, 10 min.

^bIsolated yield, after purification by flash chromatography.

^cDiastereomeric ratio (dr) determined by NMR analysis of the appropriate, characteristic proton signals in the unpurified product mixture.

^dMethanol adduct 20 (26%) was also isolated.³¹

^eReaction performed in the absence of MeOH.

^fIsolated yield of anti diastereomer, after separation by flash chromatography and recrystallization.

^gIsolated yield of inseparable 92:8 mixture of anti and syn diastereomers.

^hIsolated yield of an inseparable 93:7 mixture of anti and syn diastereomers.

ⁱIsolated yield of an inseparable 90:10 mixture of anti and syn diastereomers.