N-ferrocenoyl benzotriazole: A convenient tool for the synthesis of ferrocenoyl esters

A new synthesis methodology has been presented for the preparation of the ferrocenoyl esters. Ferrocene carboxylic acid was derivatized using direct 1H-benzotriazole/SOCl2 methodology to prepare N-ferrocenoyl benzotriazole as a convenient tool for the functionalization of ferrocene ring. N-ferrocenoyl benzotriazole was reacted with alcohols in mild conditions to prepare ferrocenoyl esters in high purity and in good yield. The solid state structure of benzyl-1-ferrocenoate, 2f, has also been determined by X-ray crystallography. In the crystal structure, intermolecular C-H center dot center dot center dot O hydrogen bonds link the molecules into a two-dimensional network. The pi center dot center dot center dot pi contacts between the cyclopentadiene rings and cyclopentadiene and phenyl rings, [centroid-centroid distances = 3.296(1) and 3.750(1) angstrom] may further stabilize the structure. Two weak C-H center dot center dot center dot pi interactions are also found. (C) 2009 Elsevier B. V. All rights reserved.