Rationalization of the stereochemistry of an addition of dialkyl phosphites to certain chiral aldimines: The experimental and theoretical approach

The absolute configuration of an α‐P stereogenic center in two diastereomeric O,O‐dialkyl α‐aminophosphonates ( 3 ), arising from an induced 1,3‐asymmetric phosphite addition to the CN bond of furfural‐derived Schiff bases ( 1 ), was established from single product ¹H NMR data. Such spectra were interpreted with anisotropic shielding in relation to the AM1 and MNDO/d structures of 3 ; the former ones turned out to be closer to the obtained experimental results (¹H NMR spectra of 3 , crystallographic database study). Since favored 3‐21G geometries of starting imines 1 were modeled as well, it was inferred that a stereochemical outcome of this reaction is governed by Cram selectivity. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:120–125, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10005