Table 2.

NHC–Cu-Catalyzed Enantioselective Boronate Conjugate Additions to Aryl-Substituted α,β-Unsaturated Esters^a

entry	aryl	R	time (h)	conv (%)b	yield (%)c	erd
1	Ph	Me	24	>98	80	96.5:3.5
2	o-BrC6H4	Me	24	>98	92	95.5:4.5
3	o-MeC6H4	Me	24	38	31	53:47
4	2-naphthyl	Me	36	>98	>98	96.5:3.5
5	m-BrC6H4	Me	18	>98	96	97:3
6	p-BrC6H4	Me	12	>98	93	98:2
7	p-CF3C6H4	Me	24	>98	93	99:1
8	p-OMeC6H4	Me	36	73	69	95:5
9	Ph	Et	18e	>98	90	94.5:5.5

^aSee Table 1.

^bSee Table 1.

^cYields of purified products.

^dDetermined by HPLC analysis. See the Supporting Information for details.

^ePerformed at –15 °C.