Table 1. The effect of base ^a .

Entry	Base	3aa		Recovery of 1a b (%)
		Yield b (%)	ee c (%)
1 d	Na2CO3	4	n.d. e	85
2	K2CO3	42	51	43
3	Rb2CO3	67	66	27
4	Cs 2 CO 3	77	72	6
5	Na3PO4	47	58	37
6	K3PO4	66	71	16
7	LiOH	36	42	47
8	NaOH	64	45	19
9	KOH	27	62	47
10	LiOtBu	37	31	25
11	TEA	3	n.d. e	71

^aUnless indicated otherwise, the experiments were performed with 1a (0.2 mmol), 2a (0.24 mmol), Pd₂(dba)₃·CHCl₃ (0.005 mmol), L10 (0.015 mmol), and base (0.4 mmol) in DCE (2 mL) at 80 °C under Ar atmosphere.

^bThe yield and recovery were determined by ¹H NMR analysis using 1,3,5-trimethylbenzene as the internal standard.

^cThe ee values were determined by HPLC analysis.

^dReaction time: 22.5 h.

^en.d. = not determined.