Table 1. Reaction Optimization Studies^a.

entry	ligand	solvent	yield (%)b	ee (%)c
1	L1	1,4-dioxane	38	8
2	L2	1,4-dioxane	80	34
3	L3	1,4-dioxane	80	24
4	L4	1,4-dioxane	78	83
5	L4	1,4-dioxane (0.1 M)	84	79
6	L4	1,4-dioxane (0.2 M)	80	75
7	L4	MeCN	71	1
8	L4	PhMe	78	22
9	L4	Et2O	71	38
10	L4	THF	70	41
11	L4	CH2Cl2	98	65
12	L4	1,4-dioxane/CH2Cl2 (3/1)d	82	81

^aConditions: 16a (0.17 mmol), [Pd₂(dba)₃] (2.5 mol %), (L1–4) (6.5 mol %). Abbreviation: dba, dibenzylideneacetone.

^bIsolated yield.

^cEnantiomeric excess determined by chiral HPLC;

^dPerformed at 0 °C.