Table 2.

Optimization of reaction parameters.^a

entry	R3, R4	pdt	solvent	additive	yield (%)b	ee (%)c
1	Bn, CF3 (2a)	7a	DCM	--	12	35
2	Me, CF3 (2b)	7b	DCM	--	12	42
3	Me, Me (2c)	7c	DCM	--	73	78
4	Me, Me (2c)	7c	DCM	--d	13	--
5	Me, Me (2c)	7c	DCM	--e	0	--
6	Me, Me (2c)	7c	DCM	K2CO3	73	78
7	Me, Me (2c)	7c	DCM	2,6-lutidine	0	--
8	Me, Me (2c)	7c	DCM	4Å MS	86	81
9	Me, Me (2c)	7c	DCE	4Å MS	87	79
10	Me, Me (2c)	7c	CHCl3	4Å MS	80	72

^aReactions conducted under inert atmosphere on 0.2 mmol scale for 2 h.

^bIsolated yield.

^cDetermined by chiral stationary phase SFC.

^dNo (R)-BINOL was employed.

^eNo SnCl₄was employed.