Hydrotris-

Synthetically useful stereoselective reductions have been possible with cyclic carbonyl compounds of rigid conformation. Reduction of substituted cyclohexanone and cyclopentan-one rings by hydrides of moderate activity, e.g. NaBH (J.-L. Luche, 1978), leads to alcohols via hydride addition to the less hindered side of the carbonyl group. Hydrides with bulky substituents 3IQ especially useful for such regio- and stereoselective reductions, e.g. lithium hydrotri-t-butoxyaluminate (C.H. Kuo, 1968) and lithium or potassium tri-sec-butylhydro-borates or hydrotri-sec-isoamylborates (=L-, K-, LS- and KS-Selectrides ) (H.C. Brown, 1972 B C.A. Brown, 1973 S. Krishnamurthy, 1976). 

Classic A/-heterocychc ligands, eg, bipyridyl (bipy), terpyridyl, imidazole, pyrazine, phenanthroline, piperazine (including alkyl- and aryl-substituted derivatives), and polypyrazol-l-yl-borates (bis, tris, and tetra), have all been found to coordinate Th(IV) chlorides, perchlorates, and nitrates. The tripodal hydrotris(pyrazolyl)borates, HBPz, have been used to stabilize organometaHic complexes (31). Bis-porphyrin Th(IV) "sandwich" complexes have been... 

Mo(V) Hydrotris(3,5-dimethylpyrazol-l-yl)borate [BH(DMPz)3] MoOCl2-C6H5Cl[BH(DMPz)3] 82JCR(S)6 ... 

S4N4 as a source thionitxosyl-metal complexes is limited to a single example. The first selenonitrosyl-metal complex TpOs(NSe)Cl2 (Tp = hydrotris(l-pyrazolyl)borate) was prepared recently by method (a). ... 

Chemistry of transition metal complexes supported by hydrotris(pyrazolyl) borates and chemistry of dioxygen complexes based on these ligands 99YGK619. 

Chemistry, syntheses, and applications of thallium(I) hydrotris(pyrazolyl)borate [TpTl(I)] 98MI44. 

Tp )FeMe] [Tp = phenyltris(3-tert-butylpyrazol-l-yl)borate] (98JA10561) and [(> -Tp )FeR] [Tp = hydrotris(3,5-diisopropylpyrazol-l-yl)borate R = Ft, CH2CHCH2, CH2T0I-P] [98JCS(CC)973, 99JCS(CC)417] are prepared by methods similar to those described for the similar non-transition and late-transition metal alkyls. 

Complex [(r] (N)-2,1,3-benzothiazole)Os(CH=CHTol-p)(CO)Cl(PPh3)2] with potassium hydrotris(pyrazol-l-yl)borate at the first stage gives the >7 -coordinated [(>7 -Tp)Os(CH=CHTol-p)(CO)Cl(PPh3)2], which eliminates triphenylphosphine on thermolysis and gives the > -coordinated [(> -Tp)Os(CH=CHTol-p)(CO)Cl (PPh3)l [98JCS(D)3501]. 

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