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The reaction of 4 equiv of LiNHAr (Ar = 2,6-06 3' 2) with a solution of ZrCl4(THF)2 in THF/pyridine yields Zr(=NAr)(NHAr)2(py)2 (1) in high yield. Zr(=NAr)(NHAr)2(py)2 reacts with 1 and 2 equiv of Me3SiCl in THF/pyridine to provide Zr(=NAr)(NHAr)Cl(py)2 (2) and Zr(=NAr)Cl2(py)3 (3), respectively. ZrCl4(THF)2 reacts with 4 equiv of LiNHAr, followed by 2 equiv of Me3SiCl (in THF), to afford Zr(=NAr)Cl2(THF)2 (4) in a high-yield, one-pot synthesis. Hf(=NAr)Cl2(THF)2 ( 5) is prepared similarly. Zr(=NAr)(NHAr)Cl(py)2 reacts with 1 equiv of K[N(SiMe3)2] in THF to provide Zr(=NAr)(NHAr) [N(SiMe3)2] (py)2 (6), which could not be converted into a bis(imido) species. Both Hf(=NAr)Cl2(THF)2 and Zr(=NAr)Cl2(THF)2 react with K2(C8H8) to provide [(?/8-C8H8)Zr(=NAr)]2 (7) and [(?;8-C8H8)Hf(=NAr)]2 (8) in high yield. Zr(=NAr)Cl2(THF)2 reacts with 1 equiv of Li(C3H4Me) in THF to provide [(r/5-C5H4Me)Zr(=NAr)Cl]2 (9) in moderate yield. An X-ray structural determination of this compound reveals a dimeric structure with bridging imido ligands. [(tj5-C5H4-

The syntheses of mononuclear complexes cis-MoVOXL (X = Cl, Br, OMe, OEt, OPh, SPh, NCS, OSiMe3) and two binuclear complexes MoV 2O3L2 of the title ligand LH2 are reported. Two forms of MoOClL, with cis oxo and chloro ligands, were crystallized, one in space group P21/n, with a = 10.440(2) Å, b = 14.260(2) Å, c = 12.041(2) Å, β = 102.76(2)°, V = 1748(1) Å3, and Z = 4, and the other in P21/c, with a = 13.564(4) Å, b = 7.172(2) Å, c = 18.242(6) Å, β = 95.19(1)°, V = 1767(2) Å3, and Z = 4. MoO(OSiMe3)L crystallizes in space group P21/c, with a = 15.923(3) Å, b = 11.141(2) Å, c = 14.186(2) Å, β = 112.64(2)°, V = 2323(1) Å3, and Z = 4, while MoO(NCS)L crystallizes in Pna21, with a = 22.471(2) Å, b = 12.136(2) Å, c = 7.138(1) Å, V = 1947(1) Å3, and Z = 4. The four structures reveal two possible conformations for ligand L:  one with trans S atoms (cis,trans-MoOClL and -MoO(OSiMe3)L) and one with cis S atoms (cis,cis-MoOClL and -MoO(NCS)L). The cis,cis isomers are converted to the cis,trans forms under reflux in MeCN at 80 °C. Only the cis,trans forms could be isolated for bulkier ligands X (OPh, SPh, OSiMe3). A short H3C···X interaction is present in the cis,cis forms:  C···Cl = 3.07 Å and C···N = 2.93 Å, for X = Cl and NCS, respectively. Infrared and electronic spectral data provide unambiguous identification of the stereochemistry of ligand L in mononuclear complexes MoOXL. Effective removal of ligand X = OR from cis,cis-MoO(OR)L (R = Me, Et) led to two binuclear complexes (MoVOL)2(μ-O) of C i and C 1 point symmetries. C i -(MoOL)2(μ-O)·thf crystallizes in space group P21/c, with a = 8.5650(5) Å, b = 15.1862(9) Å, c = 16.8038(9) Å, β = 100.183(1)°, V = 2157.1(8) Å3, and Z = 2, while C 1-(MoOL)2(μ-O)·CH2Cl2 crystallizes in space group P21/c, with a = 12.5250(5) Å, b = 24.673(1) Å, c = 12.7253(6) Å, β = 108.070(4)°, V = 3738.6(3) Å3, and Z = 4. C i -(MoOL)2(μ-O)·thf features two cis,trans-MoVOXL centers with X = μ-O, while C 1-(MoOL)2(μ-O)·CH2Cl2 contains a cis,trans and a cis,cis center. In the latter, the Mo−O−Mo link is asymmetric, allowing relief of steric crowding on the cis,cis side of the molecule.

Staurosporine (1), isolated by Omura and co-workers from Streptomyces staurosporeus, is one of the most potent known inhibitors of protein kinase C.1 It also inhibits other protein kinases in nanomolar concentrations by binding to their conserved catalytic regions.2 Our interest in staurosporine arose from two considerations. First, its unusual structure invites interesting solutions for its total synthesis.3-4 Furthermore, synthetic mastery