Table 1.

Initial ligand screen.^a

entry	L	3a:4ab	yield (%)c	ee (%)d3a	ee (%)d4a
1	P(4-MeO-C6H4)3	1:1	<20	-	-
2	BINAP	-	NR	-	-
3	dppb	>20:1	<5	-	-
4	B1	1:2.2	32	5e	55e
5	B2	1:4.5	50	45	8
6	B3	1:2.7	26	5e	45e
7	T1	1:7.0	80	83	94
8	T2	1:7.3	87	89	94
9	T3	1:3.3	76	90	81

^aReaction conditions: 1 (2 equiv), 2, [Rh(C₂H₄)₂Cl]₂ 5 mol %, L 10 mol % in PhMe at 110 °C for 16 h.

^bRatio determined by ¹H NMR of crude reaction.

^cCombined isolated yield.

^dDetermined by HPLC analysis on a chiral stationary phase.

^eOpposite enantiomer.