Low valent of Vanadium catalyst in organic synthesis

I. Oxidation of Alcohols Laxmidhar Rout, Adv. Synth. Catal. 2007, 349, 846 – 848 *clean technological process and no halogenated solvents are involved

mechanism

II.Pinacol Coupling Reaction 1. Secondary Aliphatic Aldehydes Toshikazu Hirao, J. Org. Chem. 1998, 63,

mechanism Toshikazu Hirao, Top Curr Chem. 2007, 279: 53–75

2.intramolecular coupling reaction of 1,5- diketone Toshikazu Hirao, J. Org. Chem. 1998, 63,

3.Aromatic aldehydes （ solvent ： water ） Xu, and Toshikazu Hirao J. Org. Chem., 2005, 70 (21), No addition of a chlorosilane

CAT:[V 2 Cl 3 (THF) 6 ] 2 [Zn 2 Cl 6 ] (V:II) some aliphatic aldehydes + aromatic aldehyde(bearing a chiral auxiliary ) → 1,2- diols diastereoisomeric ratios up to 91:9 and enantiomeric excesses up to 84%. Tetrahedron:Asymmetry, 1990, 1(6), aliphatic aldehydes with aromatic aldehyde(bearing a chiral auxiliary ）

III. Homocoupling Toshikazu Hirao, J. Org. Chem. 1996, 61, The yield of 2a depended on the amount of chlorotrimethylsilane 1. Coupling of Aldehydes

2.Coupling of Aldimines Bunpei Hatano, Akiya Ogawa, and Toshikazu Hirao* J. Org. Chem., 1998, 25, 9423.

mechanism

IV. Related Radical-Like Coupling Toshikazu Hirao, J. Org. Chem. 1998, 63,

[V 2 Cl 3 (THF) 6 ] 2,[Zn 2 Cl 6 ],(V:II),freshly prepared from VCl 3 (THF) 3 (V:III)by the reduction with Zn Tsutomu Inokuchi, J. Org. Chem., 1991, 16,

mechanism

b:*Carried out in CH 2 Cl 2 -THF.

Tsutomu Inokuchi, J. Org. Chem., 1991, 16,

Cyclization of Olefinic Iodoethers to Tetrahydrofurans Cp 2 TiCl 2 was found to be superior to Cp 2 VCl 2 as a catalyst under these reaction conditions Longhu Zhou, and Toshikazu Hirao J. Org. Chem., 2003, 68 (4),

V. stereoselective cyclodimerization Longhu Zhou and Toshikazu Hirao, Tetrahedron Letters, 2000, 41, 8517–8521 Reaction conditions: benzylidene malononitrile (1 mmol), Cp 2 VCl 2 (5 mol%), Zn (2 mmol), Me3SiCl (2 mmol), DMF (5 mL), Ar, rt, 3 h.

3a (24% yield with excellent diastereoselectivity (98:2) 2a (58% yield, 80:20) *3a was converted to 2a on treatment with silica gel overnight *18 h, only 2a was formed,

VI. Dehalogenative Coupling *R2 is bigger. *the coordination of the phosphorus raises the reduction capability and selectivity. *the bulky reductant is liable to approach the bromide from the less hindered side Toshikazu Hirao ， J. Org. Chem., 1993, 58 (23),

VII. A Novel C−C Single Bond Formation Yasutaka Kataoka,*J. Org. Chem. 1996, 61, V with Grinard reagent *cleavage of the C-O bond at the benzylic position was easy

As the amount of allyl bromide increased, the yield of the coupling product 1a decreased gradually while the amount of 3 increased. * clarify the effect of the added O 2

Mechanism: 1a, under high dilution conditions. Yasutaka Kataoka,*J. Org. Chem. 1997, 62,

The cleavage of the C-O bond at the allylic position also proceeded similarly.

Yasutaka Kataoka, J. Org. Chem. 1996, 61, V with ZnR 2 the alkylation of carbonyl compounds the pinacolcoupling reaction the deoxygenative coupling reaction of carbonyl compounds

Yasutaka Kataoka, Isamu Makihira, Masaru Utsunomiya, J. Org. Chem., 1997, 62 (24), a competitive reaction between an aldehyde and a ketone

*direct construction of asymmetric quaternary carbons Tetrahedron Letters, 1995, 36, V with Zn and allylic bromide

mechanism vanadium(II) species prepared in situ from VCl 3 (thf) 3 and Zn

VIII.cross-coupling reaction 1.Alkyl Halides with Aryl Griganard Reagents Shigeo Yasuda,Hideki Yorimitsu* Bull.Chem.Soc. Jpn. 2008, 81, Mechanism ：

Prove the radical intermediate

mechanism

IX. Potent Dinuclear Catalysts for Olefin Copolymerization