Table 1. Optimization of the organocatalytic conjugate addition under solvent-free flow conditions ^a .

# b	Malonate (equiv.)	Flow rate (μL min-1)	T (°C)	Conv. c (%)	ee d (%)
1	9	100 e	50	91	98
2	3	100 e	50	81	98
3	3	100 e	60	89	97
4	3	100 e	70	94	95
5	2	70 f	60	93	97
6	2	50 g	60	94	97
7	2	20 h	60	99	95

^a1 equiv. 4-fluorocinnamaldehyde, 0.6 equiv. AcOH as additive, 1 g catalyst 4 in Omnifit® column, solvent-free.

^bNo side product formation, chemoselectivity was 100% in all reactions.

^cDetermined by ¹H-NMR analysis of the crude product.

^dDetermined by chiral HPLC.

^e t _r= 14 min.

^f t _r= 20 min.

^g t _r= 28 min.

^h t _r= 70 min.