Synthesis of a new analogue of BINOL based on a homodimer of substituted 1-hydroxypyrazole

Abstract

A new potential ligand for asymmetric synthesis, based on a homodimer of 1-hydroxypyrazole, has been synthesized. The chemistry involved lithiation, iodine–magnesium exchange, magnesium–zinc exchange, and cross-coupling reactions. In a preliminary study, the chemical activity of the ligand as a titanium(IV) complex was investigated in the addition of diethyl zinc to benzaldehyde. Its activity was comparable to the corresponding BINOL–Ti(IV) complex.