Scheme 1. (i) Malononitrile, NaBH4, ethanol/water (95/5), 3 h, r.t., 80%; (ii) HPO(OEt)2, Et3N, Pd(PPh3)4, PPh3, tetrahydrofuran, 48 h, reflux, 73%; (iii) 2-(bromomethyl)pyridine·HBr, K2CO3, acetone, 3d, r.t., 58%; (iv) borane, tetrahydrofuran, 24 h, r.t., 99%; (v) 2,3-butanedione monoxime, CoBr2·6H2O, air, methanol, 5d, r.t., 45%; (vi) bromotrimethylsilane, dichloromethane, 48 h, r.t., 65% yield. The chemical structure of CoP3 is shown in Fig. 1C.
