Polymerization of rac-LA with dimethyl Cu(ii) complexes, [L_nCuMe₂] (L_n = L_A–L_F), generated in situ in CH₂Cl₂ at 25 °C.

Entry	Catalysta	Conv.b (%)	M n c (g mol−1) × 103 (calcd)	M n d (g mol−1) × 103 (GPC)	PDId	P r e
1	MeLi	99	14.27	11.44	1.50	0.47
2	[LACuMe2]	100	14.41	10.92	1.60	0.59
3	[LBCu(μ-Me)Me]2	100	14.41	12.01	1.68	0.52
4	[LCCuMe2]	100	14.41	12.77	1.52	0.53
5	[LDCuMe2]	100	14.41	11.49	1.66	0.59
6	[LECuMe2]	100	14.41	15.50	1.53	0.59
7	[LFCuMe2]	100	14.41	9.40	1.81	0.68

^aConditions: [initiator] = 0.0625 mmol; [rac-LA]/[initiator] = 100; 5.00 mL of CH₂Cl₂ as polymerization solvent; polymerization time = 2 h.

^bMonomer conversion (%) determined by ¹H, NMR spectroscopy.

^cCalculated from [molecular weight of rac-LA] × [rac-LA]/[initiator] × conversion%.

^dDetermined by gel permeation chromatography (GPC) in THF, relative to polystyrene standard (corrected using the Mark–Houwink factor of 0.58).^65,66

^eProbability of heterotactic enchainment (P_r) were calculated on the basis of homonuclear decoupled ¹H NMR spectra according to literature.^45,46