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Updated: Sep 2, 2025

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
A Practical Method for the Large-Scale Preparation of the P-Chiral Dihydrobenzoazaphosphole Core by Chemical
Jean-Nicolas Desrosiers1, Yibo Xu1, Stephanie C Kosnik1
1Chemical Development, Boehringer Ingelheim Pharmaceuticals, Inc., 900 Ridgebury Road, Ridgefield, Connecticut 06877 United States.
Abstract:
ZPhos, as an effective ligand in the Cu-catalyzed asymmetric hydrogenation of ketones and aminoboration of alkenes, is prepared efficiently from the corresponding triflate of P-chiral dihydrobenzoazaphosphole 1. However, the previous approach to 1 by chiral separation is time-consuming and costly, preventing its production and further application on a large scale. In this report, a practical method for the large-scale preparation of 1 was developed via chiral chemical resolution with (1S,2S)-diaminocyclohexane as an effective resolution reagent.
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