Influence of neutral donor ligand in the ROP of (rac)-BBL catalyzed by 1-RE^a.

Entry	Cat.	[BBL]/[RE]	Ligand	Temp (°C)	Timeb (h)	Conv.c (%)	M n,calc d (kg mol−1)	M n,exp e (kg mol−1)	Đ e , f	P m g
1	1-Y2	200	—	25	1	5	0.9	n.d.	n.d.	n.d.
2	1-La	200	—	25	1	21	3.6	2.9	1.04	0.57
3	1-La	200	DMAP	25	1	22	3.8	3.6	1.07	0.59
4	1-La	200	DABCO	25	1	7	1.2	n.d.	n.d.	n.d.
5	1-La	200	PPh3	25	1	25	4.3	1.7	1.38	n.d.h
6	1-La	200	TPPO	25	1	97	16.7	9.6	1.18	0.71
7	1-La	200	HMPA	25	1	99	17.0	9.4	1.29	0.73
8	1-La	200	TOPO	25	1	99	17.0	9.5	1.23	0.75
9	1-La	200	OP(OPh)3	25	1	25	4.3	1.6	1.35	0.63
10	1-La	200	TPPO	0	1	96	16.5	11.2	1.15	0.76
11	1-La	400	TPPO	0	4	77	26.5	15.3	1.20	0.75
12	1-La	200	TPPO	−30	24	99	17.0	11.5	1.12	0.80
13	1-La	200	TOPO	0	1	99	17.0	12.9	1.20	0.80
14	1-La	400	TOPO	0	4	96	33.1	19.2	1.09	0.80
15	1-La	200	TOPO	−30	6	99	17.0	13.0	1.09	0.80

^a[BBL] = 2.4 M.

^bReaction times not optimized.

^cDetermined by ¹H-NMR integration of BBL and PHB methine resonances in the crude reaction mixture.

^d[BBL]/[RE]/[ⁱPrOH] × Conv. × 0.08609 + 0.0601 kg mol⁻¹.

^eDetermined by gel permeation chromatography (GPC) at 30 °C in THF using polystyrene standards and corrected by Mark–Houwink factor of 0.54.⁵¹

^f M _w/M_n.

^gProbability of meso-linkages between repeat units. Determined by integration of P3HB C̲ O resonances using inverse gated (IG) ¹³C-NMR.

^h0.52 at 6 h (36% conversion).