Table 3. Completing the flow synthesis of 1: Optimization of the BH₃·DMS-mediated amide/ester reduction.

# a	Flow rate (μL min–1)		3/BH3·DMS ratio	Conv. b (%)	Chemosel. b , c (%)
	P1	P2
1 d	200	200 e	1 : 10	96	74
2	100	100 f	1 : 10	100	100
3	130	70 f	1 : 5.4	100	100
4	140	60 f	1 : 4.3	100	95
5	150	50 f	1 : 3.3	99	76
6	260	140 e	1 : 5.4	100	100
7	390	210 g	1 : 5.4	100	93

^a95-96% ee was measured in all reactions (by using chiral HPLC).

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

^c 1a formed as minor product in entries 1, 4, 5 and 7.

^dAt 50 °C.

^e t _r= 30 min.

^f t _r= 60 min.

^g t _r= 20 min.