Table 1.

Identification of the most-active catalyst and optimum reaction conditions in the phase-transfer catalyzed MIRC-reaction of bromomalonates 1 with 2

Entry	1	Cat.	Solv.	Base (equiv)	Concd.	Yielda (%)	er b (+/−)
1	1a	4a	CH2Cl2	Cs2CO3 (4×)	Ac	70	51:49
2			THF			77	43:57
3			Toluene			30	44:56
4		4b	THF			45	46:54
5		4c				40	44:56
6		5a				41	51:49
7		5c				14	52:48
8		5d				55	57:43
9		4c	Toluene	K3PO4 (10×)		45	31:69
10		4a		K3PO4 (50%) (10×)		84	50:50
11		4b				36	38:62
12		4c				48	26:74
13		4d				57	40:60
14		4e				44	31:69
15		4f				67	50:50
16		5b				30	70:30
17		5d				45	73:27
18		6				57	47:53
19		4c	Mesitylene			43	24:76
20			Toluene	Li2CO3 (50%) (10×)		7	21:79
21				K2CO3 (50%) (10×)		35	24:76
22			Mesitylene			54	22:78
23	1b					n.r.	—
24	1c					63	17:83
25					Bc	10	17:83
26					Cc	54	15:85
27					Dc	83	15:85
28					Ec	82	13:87
29					Fc	39	10:90
30		5d			Ec	61	75:25

^aIsolated yield.

^bDetermined by HPLC using a chiral stationary phase.

^cA: 3 equiv 2, rt, 22 h, 0.15 M; B: 3 equiv 1a, RT, 22 h, 0.15 M; C: 3 equiv 2, rt, 46 h, 0.075 M; D: 6 equiv 2, rt, 46 h, 0.075 M; E: 6 equiv 2, 0 °C, 46 h, 0.075 M; F: 6 equiv 2, −20 °C, 46 h, 0.075 M.