Donor Strength Determination of Buchwald-Type Phosphines.

ABSTRACT

The electronic properties of eight Buchwald-type phosphines were determined and ranked by 13C NMR spectroscopy, highlighting the sensitivity of the Huynh electronic parameter (HEP). Furthermore, the 13Ccarbene NMR signals of 19 known and new P-donor complexes in CDCl3 (HEP values) are found to be highly correlated to those in C6D6. This enables the donor strength determination of P-donors even where the complexes are unstable or undergo rapid isomerization due to transphobia in CDCl3.