Table 1.

Identification of the most active catalyst for the asymmetric α-alkylation of 7 and of the optimum reaction conditions

Entry	Cat.	Ar	Ya	Solvent	Base	T/°C	Yieldb (Conv.)c (%)	ee (%)d (Conf.)e
1	3aa	Ph	Aa	PhMe	KOH (50%)	rt	70 (~90)	34 (S)
2						−20	55 (~70)	45 (S)
3	3ba	4-tBu-Ph					30(~50)	61 (S)
4	3ca	4-F-Ph					35 (~50)	34 (S)
5	3da	3-Me-Ph					77 (~90)	55 (S)
6	3ea	3,5-Me2-Ph					47 (~60)	5 (S)
7	3fa	m-Biphenyl					45 (~60)	7 (S)
8	3ga	p-Biphenyl					65 (~80)	79 (S)
9	3gb		Ba				57 (~80)	51 (S)
10	3gc		Ca				21 (~30)	25 (R)
11	3ga	p-Biphenyl	Aa	PhMe	CsOH·H2O	−70	54 (~70)	39 (S)
12				CH2Cl2		−70	35 (~50)	38 (R)
13					KOH (50%)	−20	53 (~70)	28 (R)
14				THF			71 (~90)	7 (S)
15				PhF			82 (>90)	68 (S)
16				benzene: PhMe (2:1)			69 (~80)	82 (S)
17f							37 (~50)	57 (S)
18					NaOH (50%)		33 (~50)	19 (S)
19					CsOH (50%)		24 (~40)	65 (S)
20				benzene : PhMe (1 : 1)	KOH (50%)	−35	61 (~75)	84 (S)
21				PhMe			54 (~70)	87 (S)
22g							81 (quant)	87 (S)

^aSee Scheme 2.

^bIsolated yields.

^cJudged by ¹H NMR or TLC of the crude product.

^dDetermined by HPLC using a chiral stationary phase.

^eDetermined by comparison of the HPLC retention time and optical rotation with literature^6,9 values.

^fUsing 1% catalyst.

^gUsing 3 eq. 8.