The reaction of N,N′-dibenzyl-2-amino-4-imino-pent-2-ene, nacnac ~(Bn)H, with 1 or 2 equiv. of MgnBu_2 afforded the homoleptic complex nacnac~(Bn)_2Mg. The reaction of nacnac~(Bn)H with Mg(N(SiMe_3)_2)_2 yielded nacnac ~(Bn)MgN(SiMe_3)_2, which reacted with tert-butanol to form nacnac~(Bn)MgOtBu. The latter complex crystallizes as an alkoxide bridge dimer and is active in the ring-opening polymerisation of rac-lactide. Polymerisations at room temperature afforded atactic polylactide, while polymerisations at -17 and -26 °C afforded polylactide with a small isotactic bias (P_m = 0.52, and 0.55, respectively).
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