Optimization of Pd-catalyzed spirocyclization^a.

Entry	Pd/ligand	Base	T (°C)	31 : 32b	Yield (%)c	eed
1	Pd-PEPPSI-IPr	Cs2CO3	115	1.8 : 1	55	n/a
2	[Pd]/L1	Cs2CO3	90	1 : 1.1	11	−14
3	[Pd]/L2	Cs2CO3	90	1.7 : 1	14	4
4	[Pd]/L3	Cs2CO3	90	1 : 1.5	9	75
5	[Pd]/L3e	Cs2CO3/Ag2CO3f	105	1 : 2	8	83
6	[Pd]/L3e	Cs2CO3/Ag2CO3f	80	1 : 2.1	21	86
7	[Pd]/L3g	Cs2CO3/Ag2CO3f	70	1 : 2.2	14	98
8	[Pd]/L1e	Cs2CO3/Ag2CO3f	70	1 : 1.8	6	−53

^a[Pd] = [Pd(allyl)Cl]₂; standard conditions: Pd source (10 mol%), ligand (15 mol%), base (1.5 equiv.).

^bDetermined by ¹H NMR analysis of the crude reaction mixture.

^cYield of isolated 31.

^dDetermined by HPLC analysis.

^e[Pd]/ligand (30/45 mol%) prestirred in PhMe for 1 h.

^f2.5 equiv. each.

^g[Pd]/ligand (40/60 mol%).