Table 1.

Catalyst screening and optimization for the propargylation of benzaldehyde.^[a]

Entry	Catalyst[b]	Solvent	t [h]	Yield [%][c]	ee [%][d]
1	PA1	toluene	40	94	0
2	PA2	toluene	40	93	7
3	PA3	toluene	40	92	20
4	PA4	toluene	40	95	9
5	PA5	toluene	40	91	74
6	PA6	toluene	40	93	4
7	PA7	toluene	40	94	16
8	PA5	benzene	40	89	62
9	PA5	DCM	40	87	43
10	PA5	PhCF3	40	94	68
11	PA5	p-xylene[e]	40	92	75
12	PA5	toluene[e]	40	92	77
13	PA5	toluene[e],[f]	24	93	87
14	PA5	toluene[e],[f],[g]	64	96	90
15	PA5	toluene[e],[f],[h]	72	94	91

^[a]Reaction conditions: 1 (0.10 mmol), 2 (0.12 mmol), catalyst (5 mol%), unless otherwise specified.

^[b]All catalysts were washed with 6M HCl after purification by column chromatography.

^[c]Yields of isolated product.

^[d]Determined by chiral HPLC analysis.

^[e]Reaction conducted in presence of 4Å M.S.

^[f]20 Mol% catalyst used.

^[g]Reaction conducted at 0°C.

^[h]Reaction conducted at −20°C.