Table 2.

Results of the cyclization reaction of 2-cloropropanoyl phenylalaninol conjugates.

Starting Compd	Base	Time (h)	β-L/KP ratio (HPLC)	β-Lactam# Yield (%)	Configuration (Isomer ratio)	KP # Yield (%)	Configuration (Isomer ratio)
22	BTPP	4	89:11	24a (65)	3S,4S,2′S	NI	−
	Cs2CO3	24	93:7	24a (70)	3S,4S,2′S	NI	−
23	BTPP	4	14:86	25ab (10)	3R,4R,2′S/3S,4R,2′S (85:15)	26ab (63)	3S,5S,1′S/3S,5S,1′R (81:19)
	Cs2CO3	336	11:89	NI	3R,4R,2′S/3S,4R,2′S (85:15)	NI	3S,5S,1′S/3S,5S,1′R (85:15)
27	BTPP	5	48:52	29a (39)	3S,4S,2′R	30ab (32)	3R,5R,1′S/3R,5R,1′R (82:18)
	Cs2CO3	168	48:52	NI	3S,4S,2′R/3R,4S,2′R (73:27)	NI	3R,5R,1′S/3R,5R,1′R (65:35)
28	BTPP	56	72:28	31ab (44)	3R,4R,2′R/3S,4R,2′R (77:23)	32ab (21)	3S,5R,1′S/3S,5R,1′R (85:15)
	Cs2CO3	336	82:18	31ab (59)	3R,4R,2′R/3S,4R,2′R (78:22)	NI	3S,5R,1′S/3S,5R,1′R (96:4)
37	BTPP	6	42:58	39a (30)	3S,4S,2′R	40ab (41)	3R,5R,1′S/3R,5R,1′R (58:42)

NI: not isolated.