Poly l-pyrazolyl alkane Ligands

Submitted by DONALD L. JAMESON and RONALD K. CASTELLANO Checked by DANIEL L. REGERS and JAMES E. COLLINS  

The recent report of a chiral bis(l-pyrazolyl)methane provides the first example of L not based on pyrazole or 3,5-dimethylpyrazole. The substituted bis(pyrazolyl)methane was prepared by Method A, which gave 

Tris(l-pyrazolyl)methane was first prepared by Hiickel and Bretschneider by the reaction of sodium pyrazolate with chloroform. Trofimenko prepared the tris(3,5-dimethyl-l-pyrazolyl)methane by a similar method. More recent preparations have utilized both liquid-liquid and solid-liquid phase-transfer catalysis. The preparation of tris(l-pyrazolyl)methane (E) given below is a modification of the solid-liquid phase-transfer procedure.  

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